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The magazine for Sinclair users and TIMEX /Sinclair users

September/October 1983
Volume 3, Number 5

$2.95

BUYER'S GUIDE PART 3: SYNC AT THE LIBRARY

MACHINE LANGUAGE: Quick Draw • PROGRAMMING: Logical

Operators • Extensions to Basic • Memory Scrunching • HARDWARE: Questions &

Answers • REVIEWS: Byte-Back Modem • BOOKS • GAMES

01606

BRING YOUR COMPUTER TO LIFE

WORD PROCESSING AND REAL PRINTING
TIMEX/SINCLAIR TS1000, TS1500, OR ZX81

PROFESSIONAL WORD PROCESSING AND PRINTING
FOR LESS THAN THE COST OF A TYPEWRITER

$79.95

X-WORD ZX-101

WORD-PROCESSING

16K ROM Software
Full RS232 Interface
Word Star like commands
On-line edit to 14K with
16K RAM pack-
Total cursor control,
move, delete, etc.
Upper or lower case ASC
II character
Automatic paragraph
reformating

$250.00

PRINTER

GORILLA/BANANA

10" Carriage

5 X 7 Dot Matrix

50 Characters per sec

5 or 10 Characters per in

Tractor Feed

Now for a limited time Data-Assette offers three choices to obtain these powerful solution's:

OPTION #1 = $299

Ready to run package

• Printer

• X-Word System

• Paper Supply

• All cables
Real Cost $370.00
Your Savings $71

OPTION #2 = $399

Option #1 plus

• TS1000 (2K) new

• Overlay Keyboard

• 16K of Ram Pack
Real Cost $480.00
Your Savings $81

OPTION #3 = $499

Option #1 plus

• TS1000 (2K) new

• Fullsize Keyboard

• 32K of RAM pack
Real Cost $595.00
Your Savings $96

ORDER TODAY BY PHONE FROM OUR SPECIAL 800 NUMBER OR MAIL IN YOUR CHOICE

WE ACCEPT VISA OR MASTERCARD.

DATA-ASSETTE

All orders are subject to a $4.95 handling/shipping charge

Mail Order Department
56 South 3rd Street
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(800) 523-2909
(215) 932-4807 in PA

'If you already own a printer then X-word is available for $79.95. If you only need the printer then its cost
is $250.00. Send $2.50 for our full catalogue and receive $2.50 credit on first purchase.

CIRCLE 21 ON READER SERVICE CARD

VvV

The Direct Connection

is Here . . .

. . . foryour Timex-Sinclair computer. Memotech can now connect you to CompuServe
with our new modem package. With this introductory offer you get a 300 Baud J-Cat
Modem by Novation. . . RS232 serial interface with built-in communications software
and all connecting cables. PLUS, you get a CompuServe Demopak. password. I.D. and
log on/off procedures for a free two hour demonstration of the CompuServe Information
Service.

Memotech. the leader in add-on Timex products, introduces the modem package for
only S1 99.95 + $6.95 shipping/handling. (Suggested value S290.00).

Simply plug in our direct connect add-on products to the back of your Timex computer.
TheMemopak 1 6K sells for $49.95 *. . . 32K Memopak is $99.95 * and our best seller
64K Memopak is $149.95 *

The Memotech keyboard is priced at $99.95 *. The Centronics parallel interface sells
for $74.95 * including software, and the RS232 interfaces are $99.95 *. Printer
packages are also low. low priced.

Order at no risk (10 day money-back guarantee): Call 1 -800-662-0949
(Colorado 1 -303-986-1 51 6). Or send your name, address, phone number and a
check/money order/Visa or MasterCard number with expiration date to:

Memotech Direct Sales Division
7550 W. Yale Avenue. Denver, Colorado 80227

* Shipping/Handling $4.95: Colorado Residents add applicable sales tax

NOT JUST A KEYBOARD REPLACEMENT
BUT AN ENHANCEMENT THAT GIVES
KEYBOARD FEATURES FOUND ONLY
ON MORE EXPENSIVE COMPUTERS.

FOR FASTER & EASIER DATA ENTRY
WITH YOUR E-Z KEYBOARD . . .

Here at last, is a large 60 key "TACTILE
FEEL" keyboard that plugs into the same
connectors as the existing keyboard on
your ZX81.TIMEX/SINCLAIR 1000 or 1500.

HERE THE CLICK... FEEL THE SNAP!
for every key pressed (tactile feedback)

IT'S THE ONLY KEYBOARD WITH ALL OF
THESE FEATURES:

• 60 moving keys: solid (not rubber)

• Legends in three colors on the base (color coded by key function)

• Molded legends on keytops (no stickers)

• 8 automatic shift keys (no shifting required) for edit, delete,
single & double quotes, colon, semi-colon, function and stop

• 2 shift keys

• Numeric keypad

• 5" space bar

• No wiring required (Just plug in)
Cables and instructions are included

A custom designed aluminum enclosure (shown
above) is available for youi E-Z Key keyboard.
Measurements: Price:

EC-11 (11"X9'X3.5") 24.95

EC-14(14"X9"X3.5") 29.95

JOYSTICK: 29.95

A joystick kit that requires no wiring and functions
like the arrow keys and on your computer.
Plugs into E-Z Key 60 keyboard.

USE THIS ORDER FORM:

□Check/MO OVisa DMasterCard

Card #

Exp. Date

Send to:

E-Z HEV

Suite 75. Dept. CE

711 Southern Artery
I Quincy, Massachusetts 02169
\ (61 7) 773-1187

Qty.

Item

Unit Cost

Item Total

S&H
Unit Cost

S&H Total

E-Z Key 60

$84.95

$3.95

EC-11/EC14

$24.95/$29.95

$4.95

Joystick

$29.95

$3.95

1 1

Sub totals:

hr 1

Mass. residents add 5% sales tax

Grand total:

Signature .
Name

Address.
City

_State_

^Zip-

CIRCLE 30 ON READER SERVICE CARD

The magazine for Sinclair users and TIM EX /Sinclair users

September/October 1 983

Volume 3, Number 5

DEPARTMENTS
4 Letters

19 Read This First

6 SYNC Notes Grosjean

42 Glitchoidz Report

42 Try This Allen, Ton, Chandler

8 Just for Fun Chaiet, Farrell

Hall, Hill, Midura.Schultz

14 Perceptions Ornstein

The TS2000: An overview

20 Hardware Tips Hartung

Hardware questions and answers

29 In and Out of SYNC

Making Borders and a Bouncing Ball Grosjean

The Panasonic JR-200 Ahl

38 Letter from England Adams

Software, hardware, and Sinclair developments

44 Resources

112 index to Advertisers

SYNC AT THE LIBRARY

50 Directory of Publishers

52 TS1000/ZX81 Books

60 TS2000/Spectrum Books

62 General Books

64 The Bookshelf Goes Supernova Deeson

Survey of Spectrum books in the U.K.

70 Learning Timex Sinclair Basic Aker

Book review

71 Mastering Machine Code on Your ZX81 Garrick

Book review

72 ZX81/TS1000 Statistics Kelly

Book review

73 The ZX81 Companion Grosjean

Book review

74 Byteing Deeper into Your TS10O0 Aker

Book review

PROGRAMMING TECHNIQUES

76 The Logical Operators Aker

Using AND, OR, and NOT

80 Memory Scrunching Grosjean

Over 30 tips on ZX/TS memory saving

86 Extensions to Basic Coffey

Add new commands to your computer

90 Quick-drawl Doafces

Introduction to machine code, part 4

GAMES

96 The ZX Stock Exchange Burgio

Beat Wall Street

110 Brick Buster Thomson

Try your hand at demolition

REVIEWS

100 The Byte-back Modem Keeney

Extended hardware review

108 3D Monster Maze and Mothership Grosjean

Two game reviews

Staff

Founder/Editor-in-Chief
Managing Editor
Contributing Editor
Art Editor
Typesetting
Operations Manager
Fulfillment

Advertising Sales Manager
Advertising Coordinator

David Ahl

Paul Grosjean

David Ornstein

Diana Negri Rudlo

Karen Brown

Patricia Kennelly

Frances Miskovich

Carol Vita

Karen Musmecl

Claudia Relnhardt

The Consumer Computer and Electronics Division

Ziff-Davis Publishing Company.

President Larry Sporn

Vice President, Marketing J. Scott Brings

Vice President, General Manager Eileen G. Markowlt*

Creative Director Peter J. Blank

Cover by Bob Alese

Volume 3, Number S

SYNC (USPS: 585-490; ISSN: 0279-5701) is published bi-monthly by
Ahl Computing, Inc., a subsidiary of Ziff-Davis Publishing Company.
David Ahl, President; Elizabeth B. Staples, Vice-President; Selwyn Taub-
man, Treasurer; Bertram A. Abrams, Secretary. 39 E. Hanover Ave.,
Morris Plains. NJ 07950. Second class postage paid at New York, NY
10001 and at additional mailing offices.

Permissions: Material in this publication may not be reproduced in any
form without permission. Requests for permission should be directed to
Bette Amado, Ziff-Davis Publishing Company, One Park Ave., New York,
NY 10016.

Subscription rates: USA: One year (6 issues), $16; two years (12 issues),
$30: three years (18 issues), $42. Canada: $3 per year additional. Other
foreign: $5 per year additional.

For SYNC advertising information, contact Karen Musmeci, SYNC
Advertising Sales Manager, Ziff-Davis Publishing Company, One Park
Ave., New York, NY 10016 (phone: 212/725-4216).

All other correspondence should be addressed to: SYNC, 39 E. Hanover
Ave., Morris Rains, NJ 07950. In U.K. to: SYNC, 10 Bishops Way, Sutton
Coldfield, W. Midlands B74 4XU.

Postmaster: Send address changes to: SYNC, PO Box 789-M, Morris-
town. NJ 07960.

September/October 1 983 c SYNC

lett

Payroll

Dear Editor:

I would again like to compliment both
SYNC and Alan Pattison for an ex-
cellent program "Small Business Pay-
roll" (SYNC 3:2). However, I found that
I could not copy any of the screen dis-
plays on my printer because any key-
board input routes you to another
section of the program.

Some of the menu items I wanted to
copy are: 2, 4, 5, 6, 8. By adding the
following lines I am now able to copy
any screen display I want:

442 IF M$=

• THEN

COPY

443 IF M$=

' THEN

GOTO 440

976 IF M$=

' '

THEN

GOTO 975 (

was

978)

977 IF M$=

• THEN

COPY

978 IF M$ =

■ •

THEN

GOTO 975

1993 IF M$=

•z

' THEN

COPY

1994 IF M$ =

' THEN

GOTO 1990

3917 IF M$=

•z

' THEN

COPY

3918 IF M$=

1 THEN

GOTO 3910

4142 IF M$=

'Z'

' THEN

COPY

4143 IF M$=' 'Z'

' THEN

GOTO 4 140

To make room for these changes and

to stabilize the program (I was getting a

lot of Report Codes

due to memory

saturation), I reduced the number of em-

ployee records from 35 to 30.

I appreciate your

publishing these

valuable programs and look forward to

similar programs in future issues

Robert Keneely

125-10 Queens Blvd.

Kew Gardens, N\

' 11415

PCB Differences

Dear Editor:

Timex Sinclair users should be aware
that Timex has used several different

printed circuit board etch patterns in
producing the ZX81 and the TS1000. As
a result, the experiementer may be con-
fused by differences in the patterns
which the conductor strips make on the
solder side of the board. Practically
speaking, this means that readers
attempting to follow Figure 7 in my arti-
cle "Keyboard System Conversion"
(SYNC 2:3, p. 30) may find that the etch
pattern of their CPU board is different.

The key is to remember that, no mat-
ter what version of the PCB one has, the
pin assignments on all ICs must be the
same, all components have the same rel-
ative position, the signals of the key-
board connector must be in the same
order, and the wiring of the keyboard
conversion cable puts lines AB-A15 and
KBO-KB4 in the same order.

Readers should note that this dif-
ference in etch patterns may apply to
other products and modifications which
require that a certain signal line be
jumped or a particular trace be cut.
Experimenters should refer to a ZX81
schematic for assistance in identifying
different traces using a "variant" PCB
etch pattern or one which does not re-
semble exactly an illustration in a hard-
ware article.

Robert B. Trelease, Ph.D.
2313 5th St.
Santa Monica, CA 90405

Keyboard Bumps

Dear Editor:

After playing a few games that re-
quired fingers on several keys, I found
that I could not consistently keep my
fingers in place. After trying several
ways of creating a bump I could feel on
the keys. I settled on 5 minute epoxy. It
sticks well to the keyboard surface and
can be easily removed without damage
by a fingernail. I used a toothpick to ap-
ply a small (very small) drop in the cen-
ter of each key. After an hour, the epoxy

was fully cured, and I have a tactile key-
board that cost next to nothing.
Ted Rodgers

1157 W. Peachtree St., N.W.
Atlanta, GA 30309

Stringing along

Dear Editor:

I enjoyed Paul Wentink's "Stringing
along with the ZX81" (SYNC 3:4).
However, it does have some limitations.
It does not allow for freely formatted
data. For instance, it allows for only
numbers of the same length, e.g., 30, 40,
50, and not for 1.325,-.82, 100.367.

I am an economist, and in trying to
use the data storage capabilities of the
ZX81 to the maximum I devised a way
to store numerical data in a flexible way.
The lines below give a DATA-READ
simulation which allows for variable
number lengths and variable size arrays.
The method is flexible since you can
have the ZX81 recognize any data sepa-
rator, e.g., a space, merely by changing
the contents of the strings in lines 60, 70,
and 80.

10 LET A$=' '10,1. 235 ,

- .82, 101 .5, ' '

20 DIM A(4)

30 LET Q=0

40 LET P=1

50 FOR 1=1 TO LEN A$

60 IF A$( I )='',' ' THEN

LET Q=Q+1

70 IF A$( I )='',' ' THEN

LET A(Q)=

VAL A$(P TO I -1 )

80 IF A$( |)='','' THEN

LET P=l+1

90 NEXT I
100 FOR 1=1 TO 4
110 PRINT A( I )
120 NEXT
Barry Crozier

291 Windermere Rd., Apt. 252
London, Ont.
Canada N6G 2J9 S

September/October 1983 ° SYNC

fcfcl

What
more can

I do?"

Your computer can prob-
ably do more for you than
you originally thought
And learning to expand its
capabilities is as easy as
reading a good book.

SYBEX is the pioneer
of computer book pub-
lishing, offering over 60
titles developed for begin-
ners through advanced. They are so well
written and easy to understand that virtually
anyone can learn to operate a computer
in a matter of hours.

Your Timex/ Sinclair 1000"
and ZX81 by Douglas
Hergert ($6.95) Learn
the ins and outs of your
Timex/SinclaiMOOO" You
can learn how to connect
the computer to your
television set, program it,
perform math, make bar
graphs and play games.

The Timexi Sinclair 1000" BASIC Handbook
by Douglas Hergert ($7.95) This is the
indispensable computerside companion for
programming your Timex/Sinclair 1000!"You
will find clear descriptions, proper syntax
and examples of every keyword and function
in the Timex/Sinclair 1000~BASICvocabulary.
Timex I Sinclair 1000" BASIC Programs in
Minutes by Stanley R.Trost ($795) Get the
advantages of programming your Timex/
Sinclair 1 000" without having to learn how to
program. This collection of BASIC pro-
grams allows you to: calculate home finan-
ces, analyze business and personal invest-
ments, investigate real estate
options and much more.
More Uses for Your Timex/
Sinclair 1000." Astronomy
on Your Computer by Eric
Burgess ($8.95) Study the
stars and planets in your
own home. The ready-to-
run programs allow you to
observe constellations,

stars, planets, meteor showers
and all that is celestial -on your
television screen.

SYBEX books are available
at bookstores and computer
stores everywhere. For a free
catalog, mail the coupon or call
TOLL-FREE 800/227-2346.
Prices subject to change
without notice.

Send me D A tree catalog

D 0-099 YourT/S 1000" and ZX81 $6 95

□ 0- 1 1 3 The T/S 1000" BASIC Handbook $795

DO- 1 19 T/S 1000" BASIC Programs in Minutes $795

D ■ 1 1 2 More Uses tor Your T/S 1000. "

Astronomy on Your Computer $8 95

Add. D$2.00/BookUPS D6fe% Sales Tax CA Res

D $ 1 2 00/Book Overseas Mail
Charge my
D VISA D MasterCard D American Express

Card # Exp Date

Total Amount Enclosed $

Signature

Name

Add ress . ,

City/State/Zip

Mall to: SYBEX Inc.. 2344 Sixth St.. Berkeley. CA 94710
c 1983 SYBEX. Inc 1E9

■"1

SYBEX COMPUTERBOOKS

CIRCLE 68 ON READER SERVICE CARD

SLinc nntEE

Paul Grosjean

Sir Clive

As we all know, the ZX80, the ZX81, and the Spectrum
computers — the computers which have enabled hundreds of
thousands to enter the computer age — were invented by
Clive Sinclair in Great Britain. On June 1 1, 1983, he became
Sir Clive when Birthday Honors were bestowed by Queen
Elizabeth II. Sinclair, whose company Sinclair Research is a
market leader in volume production of personal computers,
said that the event came as a complete surprise. "More than
ever I feel committed to achieving success both in and for
Britain," said Sir Clive.

SYNC at the Library

Our theme section this issue is "SYNC at the Library."
This is a Book Buyer's Guide. We have gathered together as
many titles and brief descriptions of printed resources as we
could find, but we know the list is not definitive. The book
list for the ZX81 and TS1000 is a long one. Since Eric
Deeson has given us an overview of books from the U.K.,
the Spectrum section includes those that are currently avail-
able from U.S. publishers. The general category could be
much more comprehensive, but where could we stop? We
have just suggested a few titles.

Local public libraries can give you access to ZX/TS arti-

TS 1000

ADD-ON OFFER!

16K

Memory

Extension

for only

.S25.5CL

64K

Memory

Extension

for only

.$76.00,

Fully compatible with all Sinclair add-ons and
peripherals, and specially screened to stop
radio interference.

• No soldering * Easy to fit

• Simply plugs in the back

• Guaranteed for 12 months (64K for 3 months)

• Specially designed to prevent loss of memory / CjJ
through wobble or white out • /\\0'

• Electronics housed in elegantly
designed, hardwearing case

• All units fully tested before
leaving our factory

/J*

COMPUTERS®

664 North Michigan Avenue, Suite 1010, Chicago, Illinois, 60602

<<>

•/

CIRCLE 15 ON READER SERVICE CARD

September/October 1983 ® SYNC

cles in other publications through various readers guides
and indexes. Indexing services and data banks covering only
computer publications are now available.

We have not covered any works of fiction since at this
time we have not heard of any in which the ZX/TS com-
puter plays a role. As we would expect, computers do play a
substantial role in science fiction stories, especially some of
the more recent works. We find three main themes that
seem the most popular.

First, the computer is a tool in the hands of the forces of
Good. In such stories, it is strictly subordinate to the human
users. It is "user friendly." E.E. "Doc" Smith fans will recall
the "cubic mile" Brain in the Skylark series and The Brain
in the final story in the Lensman series.

Second, the computer as a tool in the hands of Evil for the
domination, repression, or social control of humanity. The
conflict is between human beings, but victory for Good re-
quires besting not only Evil, but also the computer. This
theme is illustrate^ by E. Hoffman Price's Operation Misfit
and Roger Zelazny's My Name is Legion (an allusion to the
unclean spirits cast out in the biblical story in Mark 5).

But perhaps the most fascinating theme is the computer
as Man's ultimate enemy. How does Man defeat the Com-
puter when it has assumed virtually the power of divinity?
We immediately think of the famous (or infamous) "Hal" of
2001 and his most recent rival "The Ultimate Computer"
designed by Gus in Superman III. The Funco File by Burt
Cole is based on The Machine which must deal the problem
of deviation in its ordering of the world.

Such works are provocative and entertaining ways of
exploring the issues that must be faced as the computer age
develops. Many more issues need to be explored, however.
What is your favorite computer related story? Drop a card

to SYNC with the title, author, and a brief statement of the
computer's role in the story. Be sure to include your name
and address. Now, did anyone read the one about the night
the ZX81 (with only a 2K RAM upgrade and a few addi-
tional chips mounted on an expansion board bought from a
SYNC advertiser) took over a large midwestern city,
and . . .

Next Issue

The theme section for our next issue will be "SYNC at the
Concert," and will gather articles, programs, and products
having to do with music and sound on the ZX/TS comput-
ers. We will also take a look at expansion keyboards.

Upcoming themes include another look at the home and
business office (including word processing packages) and at
work related computer uses.

In and Out of SYNC

The ZX80 was introduced as the first personal home com-
puter under $200. The proliferation of computers in that
price range inevitabiy invites comparisons with the ZX/TS
computer. In this issue we are beginning a new department
called "In and Out of Sync."

We are planning to have a two pronged thrust to this
department. First, we will take a close look at one of the
other computers in this lower price range. Then we will take
some programming techniques on the ZX/TS computers
and see how these are done on the machine being reviewed
and at least one other computer, or we will take a technique
from another computer and see how the same thing can be
done on the ZX/TS computers. We will begin with a look at
the Panasonic JR-200 and compare programming on the
TS1000, the JR-200, and the Vic-20. S

You won't believe the SPEED

TimEBLA5TEPi5

<«

The ULTRA-FAST machine language arcade game lor professional
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* TEACHER'S GRADEBOOK — Grade records,
Statistical analysis, and more. 16K $12.95

* NFL***** USFL STATISTICAL SUMMARY

Complete statistics for every team in the
league. 3 versions. USFL '83, NFL '81 -'83.
NFL '82 -'84. NFL covers two seasons. You
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* EPHEMERIS V — ASTRONOMERS!! 16K
Deluxe planet finder and much more. $14.95

ZX PRO-FILI

Inventory Records
Personnel Files
16K $16.95 Mailing Lists etc.

The just released, machine code updated
version of ZX DATA FINDER (below).

• Instant searches • Printer compatible

• Multi-word searches "Numeric ordering

* Z-WRYTER — WORD PROCESSING $12.95

* PROFIT PLAN — Analyze 5 proposals, 30
variables each. A MUST for entrepreneurs.

16K $12.95

* EZ-HEX — Write, edit, test, and save
machine code hex programs. 16K $12.95

* ZX DATA FINDER — Data handling fully
explained. 28 page tutorial manual. 16K

The most useful and economical program dedicated to the task of
data handling that I have found yet" SYNC. Jan • Feb , 1983 $14.95

* METAGRAPHICS — Draw and save any
graphic pattern with machine code cursor
control. 16K $14.95

* CHECKSTUB — Register and Budget.$l2.95

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1.25

September/October 1 983 e SYNC

CIRCLE 55 ON READER SERVICE CARD

Just Far Fun

Generally SYNC prefers articles in some depth to help you get more out of your
computer. However, we receive many short programs that illustrate a point,
demonstrate a technique, or show something the reader has found interesting.

"Just for Fun" shares these programs with you. If you learn something, great. If
you have some fun, great. If you have some programs that you want to share, send
them to: Just for Fun, SYNC, 39 E. Hanover Ave., Morris Plains, NJ 07950.

Survive

Robert J. Midura

8KROM;16KRAM

The object of "Survive" is to survive
long enough to obtain score points before
the computer zeroes in on your location
and blasts you. Youmanueverona21 x31

by changing the values in line 60. Use
large integers for easier games and smaller
integers for harder games.

Graphics notes:

80: T.Y.T.Y. inverse X.

110: Inverse space, inverse SCORE,
inverse space.

1030: Space, 31 periods.

The ZX Pumpkin

Mark L. Hall

8K ROM; 2K RAM; IK RAM

This year you will not have to buy a
pumpkin for Halloween, and yet you will
be ready for the trick-or-treaters with your

grid of periods using the arrow keys on 5,
6, 7, 8. Each time you land on a period,
you get 2 points. Landing on a location
that has been hit (marked with an inverse
X) results in losing 1 point. Landing on a
clear location (a space) does not affect
your score.

As you move, the computer will blast
locations according to your location and
direction. You should not stay in one
location or head in one direction for too
long or you will be hit.

The game ends when you are hit or you
move into screen column 31. Ending the
game by moving into column 31 will net
you a bonus of 100 points.

Type in the program as shown, put the
computer in SLOW mode, and type
GOTO 1000. To play again, type CONT
and ENTER. You may adjust the difficulty

Listing _

5 LET L=(INKEY»="6" HMD X<!1)
- <INKEY*="7" RND X>1>

13 LET C=(INKEY$="8" RND Y<31.1
- (INKEY|="S" RND Y>1>

IS PRINT RT X,Y; - "

28 LET X=X+L

25 LET Y=Y+C

38 PRINT RT X,Y;"U"

35 IF Y>38 THEN GOTO 110

48 LET S=5+M<X,Y> +2

4-2 LET M(X,Yl=-2

4.5 LET T«T-1

SO IF NOT T THEN GOTO SO

55 IF T>0 THEN GOTO S

60 LET T=INT <RNDi3 + 3.l

65 LET H=X+T*L

S7 IF HJ21 THEN LET H=21

S3 IF M(l THEN LET H=l

70 LET I=Y+T*C

72 IF 1:1 THEN LET 1=1

73 IF 1)31 THEN LET 1=31
75 GOTO S

88 PRINT HT H,I;"»»" ; RT H,I;"Vl
;*T H,I;V;RT H,l;'V;flT H,i;TJ

10O LET H(X,Y) =-3

105 IF HoX OR IOY THEN G OTO S

HO PRINT RT P. 11. ■ ■MMBfcfcal " M'
138 OND Y>38>

IIS STOP

188© LET X=18

1305 LET Y=l

1318 LET T=B

131S DIM M (21, 38)

1328 LET S=T

1825 FOR L=l TO 21

1030 PRINT RT L ,8; "

Robert J. Midura, 19 Merrifield St.,
MA 01605.

Worcester.

1035 NEXT L
134.8 GOTO S

ZX/TS pumpkin. To set up your ZX/TS
Jack-O-Lantern, type in the listing in Fig-
ure 1, put your computer in SLOW mode,
and press ENTER.

The first six lines of the program draw
a rough oval and paint it black. This, of
course, is your ZX/TS pumpkin. The next
four lines and the sub-routine at line 120
draw the lines of the pumpkin segments.
Lines 50 and 53 draw the stem. The next
two lines draw the eyes and nose. Lines
65-1 10 flash the message and teeth of the
pumpkin in its mouth. The subroutine at
line 100 is a half second pause so that
your trick-or-treaters can read the mes-
sage. Use BREAK to get out of the
program.

The program was originally written on
the ZX81 and expanded when I got my
16K RAM pack.

Mark L. Hall, 1705 11th St., Anacortes. WA
98221.

September/October 1983 « SYNC

VOICE SYNTHESIZER

• Now you can purchase the Zebra-Talker unlimited
vocabulary voice synthesizer for only s 59.95.

•The Zebra-Talker is TS1000 and ZX-81 compatible.
•The Zebra-Talker voice software (requires 16K) will

help you create whatever you want to say.
•The Zebra-Talker uses the famous VOTRAX SC01

phoneme synthesizer with programable pitch levels.

It produces all the phonemes required for English

and Spanish speech.
•The Zebra-Talker is very memory efficient: one single

line in BASIC will produce a full sentence.

• It is so simple to use you can add voice to any pro-
gram in just minutes.

•There are hundreds of applications in education,
robotics, speech therapy, monitoring, games, aids
for the handicapped, security, prompting, and more.

• Expansion connector for "Piggy Back" expandability.
•You can plug the Zebra-Talker's output into any

audio system, or order our #C145 Amplifier/Speaker
module with volume control for just $12.50.

• Includes assembled & tested Zebra-Talker, instruc-
tion manual, and software on cassette.

• 15-Day Money Back Guarantee.

59 95

Zebra-Talker
SPEAKER / AMPLIFIER FOR THE TS1000 & ZX-81
ORDER C145 . . . . $12.50 ORDER C141 S59.95

GREEN SCREEN I KEYBOARD BEEPER

Now Timex Sinclair users can enjoy many of
the benefits IBM and all the biggies are getting
with Green Phosphour monitors ... and at a
fraction of the cost.

• The Green Screen is a specially molded
plastic optical filter which relieves eye strain
by enhancing character contrast and by elim-
inating the components of white light which
cause eye fatigue.

• The Green Screen fits right onto the picture
tube like a skin because it is molded to
match the curvature of your TV. We also in-
clude some invisible reusable tape for secure
fastening.

• The filter material that we use is just right.
not too dark nor too light. The result is a
really eye pleasing display.

• The Green Screen will fit any 12" TV or
monitor and can easily be trimmed with a pair
of scissors to fit any smaller size.

Order C1 40 $1 2.95

Experience for yourself how much the Key-
board Beeper improves the use of your
TIMEX keyboard. Simply plug it into your
computer's expansion connector and hear a
beep whenever a character is accepted by
the computer's keyboard input routine. No
software is required. Features expansion
connector for RAM etc.

BONUS 1 • You can trigger the beep from
Basic. Great for program prompts, timers,
BONUS 2 • A beep every 9 minutes will
remind you that your computer is on.
ORDER #C1 33 $19.95

HE ZEBRA KEYBOARD

1— Superior Quality: Same key mechanism as
used by IBM, Texas Instruments, Hewlet Packard,
and others. Full travel, gold inlaid contacts for
over 10 million operations.

2— Professional Full Size Layout: 40 keys corres-
ponding one to one with your computer's, plus
space bar in case you do word processing.

3— Looks Good & Feels Good: Attractive custom

molded enclosure matches your system. Sharp

TS1000 legends in two colors are easy to read and

will never wear off.

4 — Easy Installation: No soldering or technical

knowledge required. Done in minutes with simple

instructions.

ORDER C142 NEW LOW PRICE $69.95

The TimSX Sinclair Printer for your Timex Sinclair 1000
or Sinclair ZX81 prints 32 colums wide, two lines per second, with full
graphics and text capability. The TS2040 prints silently in two modes: 1)
full-screen printing with single-key copy command, and 2) program-
controlled printing allowing for custom control of the printing format. The
TS2040 connects easily to your computer, has simple ON/OFF controls,
comes with one roll of paper, easy to understand instructions and a 90-day
limited warranty. Order Zebra Cat. f*C 144 $84.95

Printer Paper

THERMAL PAPER FOR THE TS2040
SIX ROLL PACK #C143 $11.90

•Canadian Orders Add 57 00 Per Printer Plus S3 50 Per Paper 6-Pack For Snipping

SUGGESTED RETAIL

$99.95

ONLY

$84.95

Timex Sinclai
2040 Printer

FORZX81
& TS1000

Tech Info & NY State cal
(21 2) 296-2385 9-5 EST

ZEBRA SYSTEMS, INC.

78-06 Jamaica Ave. Dept. B, Woodha ven, N-Y. 11421

§■■■■■■■1 CIRCLE 79 ON READER SERVICE CARD

ADD S3 00 PER ORDER

FOR SHIPPING

WE ACCEPT VISA, MASTERCARD

CHECKS. MO

COD ADO S3 00 EXTRA

NV RESIDENTSADDSALESTAX

OVERSEAS FPO.APO. ADD 10".

DEALER DISCOUNTS AVAILABLE

To run in IK enter the program in
Figure 2. put the computer in SLOW
mode, and hit ENTER. This version does

not have the same features as the 2K
version does, but it shows some good
memory saving techniques.

10 - 3P ■■ -= TO 34

-- LE <=30-20*SIN 4.0*PI)

g 7
33

PRINT P T l 13 TREAT
GOSUB 100

20 FOB ■■ = ■ : : . 5 - - .

25 PLOT <

100

GOTO 3E

FOR T-l t- 55

30 NEX1 ■

ICE

NEXT T

35 NEX1

- L0

RETURN

iO LET c rfl

4-3 GOSUB 120

4-5 i-ET D = 15

120

-IE
130

FOR ■ =5 TC 34 3TEP -

_eT , =30-: -3 in 40*P T
,0T •

4- GOSUB 120

50 PRINT PT 3 jm

135
140

LOT 6 3--
NEXT

53 PRINT st j. r ■

4-5

RET ■

5j PRIN1 h; 3 li W m ' PT 8 18

60 PRINT fit 12 D * *

Graphics notes:

5S PRINT fiT d 13 '■.■■.*

INUERSE 5PRCE C2)

'0 GOSUB 100

INVERSE SPACE i

30 PRINT pt r. 13 TRICr

INUEF 5E 5PRCE 2,3 =

82 GOSUB 100

INUERSE 5PF

Si PRINT RT D 13 JR

-■- GOSUB '00

2 , : i £.3.i

Figure 2. IK Version.

10
15

2E
30

3=-

53 PR

FOP D=S TO 34

^tT - =\'hl 30-20*SIN

FOP ' =< TO ^2- ■

plot • c

NEXT ■
NEXT C
LET 3=15

print p t : ■■

JT hT

PRINT ht yRL 3

PT JHL 8 '. HL "18 ' " '

PRINT c- yflL IS

PRINT hT D , URL "13"

70 RRNC EXP I

30 PRINT fiT 3 13 BOO

82 RflND EXP I

3-5 GOTO URL '65"

Graphics notes:

30 INVERSE SPACE 12

E3 INUERSE 3PP3E [2

w. trigger
&cursor

DUAL TRACE SCOPE'

1 55,000 samples per second High Resolution Printer Plotter
Works with ZX81 /TS1 000. 1 6K HAM ZX or TS2040 printer &

our Analog Interlace Board Cassette tape 4 manual

$35.

FREQUENCY ANALYSIS- FFT.
Fast Fourier Transform on EPROM.

4K ol Z80 code 256 points of magnitude & phase data
calculated in one second This can be used as a subroutine
with the SCOPE to display Irequencies up lo 75Khz Two
2716s or one 2764 & docs 57c

ANALOG INTERFACE BOARD

8 channels A/D ■ 8 channels D/A High Speed 1 6 micro-
seconds A/D convert time Easy to program Many Jumper &
switch selectable options Has features which allow easy
interlacing to other micros such as TS2000. TRS-80, Apple.
CBM 64. Jupiter Ace. others Manual w/software You must
see spec sheets 10 appreciate this board $1 95

EPROM BOARD containing SCOPE & FFT at RK to
1 6K. The Basic part of the program is transferred up to RAM
lor use Consists ol lour 271 6 s on the Hunter board with
piggyback connectors

EPROMS alone-inquire

ANALOG INTERFACE with EPROM

Board attached and piggyback mounting
Box and ribbon cable mount lor Analog Board

HIGH RESOLUTION PRINTER

Graphics data acquisition, averaging. & scaling routines
Graticule optional Can be used with or without Analog
Board The graphs on the nght are of heartbeats captured
with this program, an electrocardiograph, and the
hardware pictured
Cassette tape & manual Terrific value $35

$100

(omputer^lontinuum

301 Sixteenth Avenue
San Francisco, CA 941 18

(415)752-6294

When our Analog Board and new soltwa.e are coupled with the T.mex computer & printer we realize
ST„ e m n ' a "? n , & C ° n ! , ° l f^"* which IS -"itched by anything else In its price range The software we now
ofler demonstrates only a few ol the high quality applications which are now possible

BUFFERED BUSS-

DEVELOPEMENT BOARD

KIT $65. Bare Board $35.
Application Book $10.

See
Mar &
,0__flf'/ July 83

== — tteaaJ sync

mag

CONNECTORS ^biX

Gold plated ribbon cable connectors for RAM or
peripherals Assembly w/8 " cable *1 g

We can add more connectors to the assembly or
build to your specs

TERMS

please add a minimum ol $3 on ANY order. California residents
please add 6'-!!% tax To order send check or money order or call for
COD

UHF MODULATOR $15.

Switch to ch 33 to remove TV interference
Solder on computer's circuit board in place of

the VHF unit

BUSINESS/FILE

MANAGEMENT PROGRAM

An electronic file cabinet w/sorting.
editing & printer format commands
Poweful & easy to use
ideal of mailing lists

SUM

only $10.

but ds with all of our products.
worth much more

FREE CATALOG

Explaining our
applications.

products and

Write or call (41 Si 752 6294

CIRCLE 17 ON READER SERVICE CARD

September/October 1 983 « SYNC

ZEBRA JOYSTICK ADAPTOR

Allows you to connect any Atari compatible joystick to your ZX81 or TS1000

8 DIRECTIONS,

+ FIRE

CONTROL

EXPANSION

CONNECTOR FOR

YOUR MEMORY,

PRINTER, ETC.

SIMPLY

PLUG IT

IN.

6 JOYSTICK GAMES $9.95
ATARI JOYSTICK $6.50

ADAPTOR $19.95

The ZEBRA Joystick Adaptor comes
assembled and tested with simple
instructions to make joystick
versions of most action games.
Use your own Atari compatible
joystick or add $6.50 for a
genuine Atari Joystick.
15 DAY MONEY BACK
GUARANTEE

ONLY

$19.95

WITHOUT SPEAKER

$24.95

WITH SPEAKER

i Add amazing sound effects to your games
1 Easy to program in BASIC

■ Wide frequency range.

■ Assembled and tested, with Demo software

AMAZING
SOUND EFFECTS

SUPER GAMES

ZEBRA LIGHT PEN

• Fun to experiment in BASIC

• Complete package includes:
-Light Pen

-Computer interface Module
-Demo Program Listings

• Assembled & Tested

ORDER C109 $24.95

$1995
$14.95
$12.95

C110

C112

Keyed & Labeled ?X Connector $5.95
Universal Prototyping Board . S9.95
Expansion Connector S2.50

IMPORTANT! All ZEBRA products
can be piggybacked in any order.
Your memory, printer, etc. will plug
into the last one

15 DAY MONEY BACK
GUARANTEE ON ALL
ZEBRA HARDWARE.

Tech Info & NY State call
(21 2) 296-2385 9-5 EST

ZEBRA SYSTEMS, INC.

78-06 Jamaica Avenue, Dept. B Woodhaven, New York 11421

Order Toll Free
800-221-0916

FOR SHIPPING

WE ACCEPT VISA MASTERCARD

CHECKS MO

COD ADDS3 00EXTRA

NY RESIDENTS ADD SALES TAX

OVERSEAS FPO APO ADO 10".

CIRCLE 80 ON READER SERVICE CARD

teTFTTira

CASSETTES

NEW!
LOWER PRICES
LONGER LENGTHS

DATA TRAC I C-06, C-12, C-24

From the leading supplier ol Computer
Grade Cassettes, new. longer length C 12 s
(6 minutes per side) provide the extra lew
leet needed tor some 16K programs.

Premium 5 screw shell with leader
— BASF tape

Internationally acclaimed.
Thousands ol repeat users.

Error Free • Money back Guarantee

1 Dozen

2 Dozen

C-06

700

1300

C-12

750

14 00

C-24

900

17 00

250

4O0

cC\& 500 C12s 38 tf each

-ptji-^^ Shipping $17 00/500

3*^*^ w/labds add 4« w/bo«es add 15«

TRACTOR FEED • DIE-CUT
BLANK CASSETTE LABELS

$3.00/100 $20 00/1000

CASSETTE
STORAGE CADDY

Holds 12 cassettes w/o boxes
includes edge labels

$2"

and Index card

BASF QUALIMETRIC
asa I FLEXI-DISC

S M 'i 5'/4 SSDD, Soft Sect
?2^J Liletime warranty!

$26.95/10 $12000/50 $21500/100

MICRO CASSETTES
in convenient short lengths

MC-10

MC-20

MC-30

1 Doz

1650

1800

1900

2 Doz

32 50

34 50

36 00

Same superior tape in
premium shell with
lees Includes box

SHIPPING/HANDLING S3. 50

Any quantity (except 500 special)

NOTE: Outside 48 Contin States shipping
S3 50 PLUS $1 per caddy; per dozen cas-
settes or dozen boxes: per 10 discs

In Cont. U.S. shipments are by UPS
unless Parcel Post requested.

California residents add Sales Tax

WRITE FOR FREE BROCHURE
ASK FOR QUANTITY DISCOUNTS

for IMMEDIATE SHIPMENT,
^ on Credit Card Orders

Call 213/710-1

YORK lOTomputerujore

24573 Kittndge St #S . Canoga Park. CA 91307

CIRCLE 78 ON READER SERVICE CARD

Obtuse Triangle

Michael W. Schultz

This program will draw an obtuse tri-
angle, which is any triangle with an inner
angle greater than 90 degrees. This is
done by drawing line BC (lines 10-40) and
then two oblique lines starting at each
end of line BC and have them converge
on point A (lines 50-100). The resulting
drawing will be the obtuse triangle ABC.

Enter the program in Listing 1. Hit RUN
and ENTER in either the SLOW or FAST
mode. Notice the uneven spacing caused
by the approximated PLOTting of X and
Y in the long side AC. This can be rem-
edied by inserting the lines in Listing 2.

Michael W. Schultz, 3650 Mossvale Dr. 20-D.
Mobile, AL 36608.

Listing 1.

S REM ' OBTUSE TRIBNGLE"

lO LET Y=20

SO FOR X=20 TO 40

33 PLOT X,Y

tO NEXT X

so i_et x=ae

SO FOR Y=20 TO 30

70 PLOT X . V

30 PLOT 3tX-20 . t

90 LET X=X-1

lOQ NEXT Y

110 PRINT ftT 6.5: "P."

128 PRINT FIT 12.io.-B"

130 PRINT RT Xl'.ao; "C"

14.0 PRINT RT 1*; lOi "OBTUSE TRIrt

M3LE BBC"

.i_C

OBTUSE TRIANGLE BBC

. Listing 2._

S& IF YOB THEN GOTO HO
92 PLOT 3»X-19.Y
94. PLOT 3*X-18^Y

Message Destruct

Joe Chaiet

Type in the program, and then SAVE
it. After SAVEing, put the computer in
SLOW mode and type RUN and ENTER.
Try to incorporate this technique into
your own programs.

Joesph Chaiet. 25 Cherry Hill Rd., New Paltz, NY
12561.

IB PRINT "THIS DOCUMENT IS SEC

20 PRINT "IT UILL SELFDESTRUCT
IN

21 PRIMT RT 5 .5; "MEMORIZE TH15
NOU"

22 PRINT RT 9.5.; " STATION 7 15
READY"

30 PRINT RT 1 .27: "UNITS"

40 FOR X=10 TO STEP -1

SO PRINT RT 1,24.x." ■

60 NEXT X

78 NEU

Train Revisited

John C. Hill

8K ROM; 2K RAM

SYNC 3:2 is the first issue I have seen,
and I enjoyed the "Just for Fun" column.
It is amusing and instructive— more fun
than reading instructions.

However, the pixel that wanders off
into the air above Joe Chaiet's train did
not seem to go far enough. The train
needs more "smoke." The program below
is my doodling to that end. Type in the
lines. Be sure you are in SLOW mode,
and press RUN and ENTER. Watch the
smoke !

John C. Hill. 4777 - 119th Ave.. S.E.. Bellevue,
WA 98006.

FIRE UP THE T

S print RT 4,4
Kh IN

10 LET H=20

20 FOR B=i TO 22

25 PRINT hT 21,0

30 PRINT RT fl,B; "' C

4.0 PRINT RT R-1,8

50 PRINT RT fl-2 B

50 PRINT P.T Q-- =

78 PRINT hT 0-5,8-1;

50 PRINT HT R-7 . B-2'

20 PRINT hT R-9,B-3;

5= IF B = 5 THEN GCSUB 130

94 IF B=5 THEN PRINT P,T 6.1c

95 IF B=5 THEN PRINT RT 7,7; "L
ET *ER GO. "

96 IF B=5 THEN PRINT PIT R-4,B +

= 7 IF B=6 THEN PRINT AT R-5,B+

9S IF B=6 THEN PRINT RT H-6,B+

IF 6=6

THEN PRINT

A" 1 "

R-?

100

IF B»7

THEN PRINT

fl-4

E -

102

IF B=7

- HEn PRINT

A -6

4; "

103

IF B=7

THEN PRINT

PIT

fl-7

105

NEXT B

110

120

SOTO f

130

FOR 1=1 TO 18-3*8

_iO

NEXT I

150

RETURN

Strange Listing

David Farrell

Type in the following program. With
the computer in either FAST or SLOW
mode press RUN and ENTER. Observe
the results.

David Farrell, PEAK Software. PO Box 8005. Suite
231. Boulder, CO 80306. Reprinted with permis-
sion from PEAK Software.

10 LIST

SO SOSUB 8888

313 5TOP

eaaa let ameh=peek lS3B6+2se>*PEH

15397
=310 LET INCR=302O
:322l LET RMEM=RMEM + 1
503O IF BMEM=PEEK 164-00 t256*PEE

1540 1 THEN RETURN

34.0 LET PKR=PEEK AHEH
?3SO IF PEEK fiMEM=iia THEN GOTO

|3|a i |F ) PKfl<12S THEN POKE RMEM , (

t=KR-128) >Kn>=X2e ™ EN P0KC ftMEH '
9888 GOTO INCH

September/October 1983 • SYNC

New Product Reports...

MKIV Keyboard

Just released this Spring is the MKIV Keyboard
from E. Arthur Brown Company. Designed to upgrade
the TI ME X- Sinclair 1000/ZX81 computer, this key-
board has some remarkable features. For one thing, it's
made with very high quality keyswitches. The resulting
action of the keys is just like that found on computers
costing thousands more. Keys spring back up promptly
after pressing... they never stick and always make the
electrical contact needed for data input.

Another feature of the MKIV is the keytops them-
selves. The legends are installed with a sophisticated
sublimation process. Rather than being painted,
molded, or simply stuck on, they're actua'ly impreg-
nated into the plastic. This results in smooth faced
keytops with legends that are virtually impossible to
wear out. Each key is light gray colored with red and
black legends.

The MKIV Keyboard Shown With Accessory Numeric Keypad.

There are 41 keys on the MKIV Keyboard. That's
the standard 40 Timex-Sinclair keys plus a full length
space bar. In the future, there will also be a 19 key
numeric keypad accessory that will simply plug onto a
jack in the side of the keyboard. ( Note: Photo shows 1 2
key prototype keypad.) At present, the Numeric key-
pad is not yet available.

The price of the MKIV Keyboard is $89.95 plus
$4.95 for shipping and handling. It carries a 90 day
warranty and a 1 day, money back free trial. Contact
E. Arthur Brown Company, 1702-SYN Oak Knoll
Drive, Alexandria, MN 56308 to order. For those
interested, the company also offers a free catalog of
other TS1000/ZX81 Accessories.

High Speed Word Processing/Typing

Memo-Text is a new TS1000/ZX81 word pro-
cessor from E. Arthur Brown Company that features a
unique high speed character entry routine. You can
type at full speed without having to wait for the com-

puter to catch up. This speed is maintained until the
screen fills and then your text just scrolls upward for
more character entry.

Another feature of the Memo-Text program is the
ability to handle text and data files and to LOAD/
SAVE them separately or all at once. Automatic print-
ing of form letters, invoices, or other personalized mass
correspondence is entirely within the scope of the sys-
tem. Text formatting capabilities include fast scroll
scanning of files, finding, exchanging, and moving
block., of text, amending, renaming, deleting text files,
double sized letters, centering, pagination, headers,
indentation, and several other features. All keys have
full repeat capabilities with Memo-Text. Typing is just
like using a typewriter. That is, all text is read by the
printer as lower case unless shifted.

One very important consideration for potential
Memo-Text buyers is the necessity of using it with a
Memotech Centronics interface and full size printer.
The program is designed to interact with the lower case
capabilities of this interface and won't give a printout
without it.

Memotext handles 16-64K of RAM and sells for
$48.95 plus $3.95 for shipping and handling. Order
from E. Arthur Brown Company, 1702-SYN Oak
Knoll Drive, Alexandria, MN 56308. Those of you in
need of a full size printer to use with Memo-Text might
consider the Seikosha Printer package. It consists of an
80 character dot matrix printer, the Memotech Cen-
tronics interface, a hookup cable, and paper. To order,
send an additional $339.95 plus $3.00 for shipping and
handling.

Seikosha Printer Package

Business Programs That Read Data Tapes

Mega software is a new series of integrated software
I for the TS1000/ZX81 from E. Arthur Brown Com-
pany. It consists of programs that can actually read
data tapes produced by other programs within the
series. The data read is then used by the present pro-
gram to update its own data files. For example, the
invoicing program can be used to send bills to cus-
tomers and then its data tape can be read by the
accounts receivable program to update receivable
files. You don't have to manually re-enter the billing
information.

There are two integration groups in the Mega series.
The Mega Master group consists of a desk top or-
ganizer, a spreadsheet, a word processor, a data base, a
statistical analyzer, and a graph plotter. The Mega
Wealth group is a small business set up. It consists of
an invoicing program, accounts receivable, accounts
payable, an inventory program, and a net earnings pro-
gram which produces profit/loss statements and

balance sheets. Each program works for 16-64K of
RAM and sells for $20-$25. For more information
write to E. Arthur Brown Company, 1 702-SYN Oak
Knoll Drive, Alexandria, MN 56308.

New Catalog
Addresses Compatibility

A new peripheral and software catalog which
addresses the problems of peripheral and software
compatibility has just been announced by the E.
Arthur Brown Company. According to their president,
Eben Brown, peripheral compatibility is the future of
TS1000/ZX81 computing. This new catalog tells you
what works with what... saving you time and money by
avoiding bad purchases. The catalog contains over 1 30
new products with in-depth descriptions and photos.
For your free copy, write: E.Arthur Brown Company.
1 702-SYN Oak Knoll Drive. Alexandria. MN 56308

E. Arthur Brown Company

1 702-SYN Oak Knoll Drive, Alexandria, MN 56308
612/762-8847, 612/762-1631

New Catalog

Over 1 30 exciting new
ZX8 1 /TS 1 000 products: Memory
expansion, keyboards, mass stor-
age, printers, etc. Software includes
personal, business, technical ap-
plications and arcade games. Order
your Tree catalog today!

Order Blank

Qty

Item

Ea.

P&H

Total

MKIV Keyboard

89.95

4.95

Memo- Text

48.95

3.95

Seikosha Print. Pkg.

339.95

6.95

Free Catalog

N/C

Shipping not to exceed $6.95 in U.S.A.
Foreign customers call or write for shipping charges.

Payment Method

DCheck □ Money Order DVisa □ Mastercard

Card #
Name
Address
City

Exp.

State

Zip

Send Your Order To:

E. Arthur Brown Company

1 702-SYN Oak Knoll Drive

Alexandria, MN 56308

612/762-8847, 612/762-1631

CIRCLE B ON READER SERVICE CARD

perception

David Ornstein

The TS2000 Series

Overview

The TS2000 series of computers claims
an extensive group of features 1— oth
hardware and software. The machines
feature 24K ROM. The TS2048 has 16K
RAM at its disposal while the TS2068
wields a well-utilized 48K RAM.

CPU and Operating System

The TS2000 uses a Z80A microproces-
sor running at 3.5MHz. It contains a few
buffers, either 2 or 6 RAM chips, 2 ROMs,
and the piece de resistance: a 64 pin
custom chip designed by a few wizards at
Timex.

The TS2000 features a full-sized 24K
operating system (OS) which provides the

Basic interpreter, full-channeled I/O fa-
cilities, and a function dispatcher that the
user can call to have both simple and
complex functions performed for him by
the system, thus utilizing the system's
facilities, and not duplicating them.

The TS2000's native language is Basic.
It packs all the standard Basic statements
including PRINT, INPUT, IF...THEN,
FOR...NEXT, READ...DATA, etc. A full
list of commands is given in Table 1. The
functions are listed in Table 2.

The Display

The TS2000 supports several different
display options. These include 32 column
display, 64 column display, Hires screen
of 256 x 192 pixels, Hires screen of 512 x
192 pixels, page switching, and an en-

. Table 1 . List of Commands. _

Beep x,y
Border x

BRIGHT x

CAT "m","volspec"
CIRCLE, x,y,z
CLEAR

CLEAR x

Sounds a note through the loud-
speaker whose duration is x seconds,
and is y semitones above middle C
(or below if y is negative).
Sets the border color to color x.
Colors:

Black 4 Green

1 Blue 5 Cyan

2 Red 6 Yellow

3 Magenta 7 White

Sets brightness level for subsequently
printed characters. If x=0 then nor-
mal brightness; x= 1 for bright; x = 8
for transparent.

Lists all files on the specified volume
on the screen.

Draws an arc of a circle whose cen-
ter is at (x,y), and whose radius is z.
Deletes all variables, freeing the
space that they occupied. Does RE-
STORE and CLS, resets the PLOT
position to the bottom lefthand cor-
ner, and clears all pending GOSUBs.
Like CLEAR, but, if possible, the
RAMTOP pointer will be set to x,
leaving all memory beyond location

CLOSE #c

CLS

CONTINUE

COPY

DATA ei,e2, . . . <
DEF FNv(v,,v 2

hanced color-resolution mode. The ma-
chine provides connections for a B&W or
color TV, an RGB monitor and composite
video.

The Keyboard

The keyboard is a 42 hard-key key-
board, including a full-sized space bar
and shift keys on both sides. The key-
board is full-sized and provides real tactile
feedback (i.e., the button actually pushes
down). The operating system provides for
single key entry of all keywords.

Interface and Connectors

The cassette interface on the TS2000 is
a step above the one on the TS1000,
although the one provided with the
TS1000 is sufficient for the type of jobs it

DELETE x.y

x out of the reach of BASIC.
Closes the specified stream, after
fiusing the appropriate buffers where
necessary.

Clears the main screen.
Continues executing the currently in-
memory program where execution
left off.

Sends a copy of the screen to the
printer.

Part of the data list. Must be in a
program.
v„)=e User-defined function definition;
must be in a program. Each of
the v, V! to v n must be either a
single letter or a single letter fol-
lowed by a dollar sign "$" for
numeric and string arguments,
respectively.

Deletes lines from the program
whose line numbers range from x
to y. If the x is omitted, then
deletion starts at the beginning of
the program. If the y is omitted,
then deletion continues to the
end of the program.

September/October 1 983 » SYNC

Table 1. Continued.

DIM V(X!,X2, • • ■ X n )

DIM v$(x!,X2, . . . x n )

DRAW x,y
DRAW x,y,z

ERASE "m'V'filespec'
FLASH x

FOR v = x TO y

FOR v=xTOy STEP Z

FORMAT "m'V'volspec'

GOSUB x

GOTOx

IF x THEN s

INKx
INPUT . . .

INVERSE x

LET v=e

LIST
LISTx

Creates an array with the name v
and sets it up as an array of
characters of n dimension, which
are: x u x 2 < . . . x n .
Creates an array with the name
v$ and sets it up as an array of
characters of n dimension, which
are: xi,x 2 , . . . x n . This may be
considered as an array of strings
of fixed length x n with n-1
dimensions x\ . . . x n _i.
Equivalent to DRAW x.y.O.
Draws a line from the current
plot position moving x hori-
zontally and y vertically relative
to it, while turning it through an
angle of z radians.
Removes specified file from the
specified volume.
Defines whether subsequently
nrinted characters will be flash-
ing or steady. x=U for steady,
x=l for flash, x = 8 for no
change.

Equivalent to FOR v = x TO y
STEP 1.

Deletes any simple variable v
and sets up a control variable
with the value x, limit y, step z,
and looping address referring to
the statement after the FOR
statement.

Formats the media on the speci-
fied volume, and assigns to it the
specified volume name.
Calls the subroutine at line x.
Note that x may be an expression
like 200*z+1000.
Jumps to line x, or, if there is no
line x, to the first line following.
If x is true, (i.e., non-zero), then
s is executed. Note that s in-
cludes all the statements to the
end of the line.

Sets the ink (foreground) color of
subsequently printed characters.
The ". . ." is a sequence of IN-
PUT items, separated by com-
mas, semicolons, or apostrophes.
An INPUT item can be:

(1) Any print item not beginning
with a letter.

(2) A variable name.

(3) LINE, followed by a string-
type variable name.

The PRINT items and sepa-
rators in (1) are treated exactly
the same as in a PRINT state-
ment except that everything is
printed at the bottom of the
screen.

Controls inversion of sub-
sequently printed characters. If
x = 0, then no inversion is se-
lected and all characters are
printed as ink color on paper
color. If x = 1 , then inversion is
selected and all subsequently
printed characters are printed as
paper color on ink color.
Assigns the value e to the vari-
able v.
LIST0

Lists the program starting at line
x, making x the current line.

LLIST
LLIST x

LOADf

LOAD f DATA
LOAD f DATA $0
LOAD f CODE m,n

LOAD f CODE m
LOAD f SCREENS

LPP.INT
MERGE f

MOVE "m'Y'old
filespec",
new filespec"

NEW

NEXTv

ON ERR CONTINUE

ON ERR GOTO x

ON ERR RESET
OPEN #c,"m","filespec'

OUT x,y
OVERx

PAPER x

PAUSE x

PLOT x,y
POKE x,y
PRINT . . .

LLIST

Like LIST, but listing comes out
on the printer instead of the
screen.

Loads program and variables
Loads a numerical array.
Loads a string array.
Loads at most n bytes, starting at
address m.

Loads bytes starting at address
m.

Loads a screen picture.
NOTE: For any of the above
forms of the LOAD command,
and also for the SAVE,
MERGE, and VERIFY com-
mands, if an* is inserted after the
command (e.g., LOAD*f), then
the operation will take place on a
disk-like device, and not on the
tape.

Like PRINT, but uses printer in-
stead Of SCICCii.

Like LOAD, but merges instead
of deleting memory first. All
forms as per LOAD.
Renames the old file to the name
new filespec.

Clears memory including pro-
gram, variables, etc., up to
RAMTOP.

Marks the end of a loop.
Continues execution oi program
where the last trapped error
occurred.

Sets up the system so that the
computer will jump to line x if
an error occurs. The pro-
grammer may then handle the
trapped error as he desires.
Turns off error trapping.
Opens a stream identified by c
and ties it to the device specified
or file on the device specified.
Outputs byte y to port x.
Controls overprinting of sub-
sequently printed characters.
Like INK, but controls paper
(background) color.
Stops operations for x sixtieths of
a second, (i.e., PAUSE 120 waits
for 2 seconds) or until a key is
pressed. PAUSE waits forever
until a key is pressed.
Plots an ink spot at pixel (x,y);
moves plot position.
Places the value y in memory
location x.

The ". . ." is a sequence of
PRINT items, separated by com-
mas, semicolons, or apostrophes.

A semicolon between two
items has no effect; it is used
only to separate the two items. A
comma outputs the comma con-
trol character, moving the print
position to either column or
column 15. An apostrophe out-
puts an ENTER character.

At the end of a PRINT state-
ment, if it does not end with a
semicolon, a comma, or an apos-
trophe, then an ENTER charac-
ter is output.

September/October 1983 «= SYNC

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Table 1. Continued.

RANDOMIZE
RANDOMIZE x

READ vi,v 2 , . . . v n
REM . . .

RESET (#c) (*)

A PRINT item can be:

(1) Empty (i.e., nothing).

(2) A numerical expression.

(3) A string expression.

(4) AT x,y: sets the print position
at line x, column y.

(5) TAB x: Outputs spaces until
column x is reached.

(6) A color item which takes the
form of a PAPER.INK,
FLASH, BRIGHT, INVERSE
or OVER statement.

(7) A stream specifier (e.g., #6).
RANDOMIZE

Sets the seed for the random
number generator to x. If x=0,
then the seed is given the value q,
where q is the number of seconds
times 60 that the computer has
been on.

Read values for the specified
variables from the DATA list.
No effect. REMark or RE
Minder. The ". . ." can be any
sequence of characters except
ENTER. This includes ":" so no
statements are possible after the
REM on the same line.
The arguments in parentheses
are optional. If no arguments are
given, then the RESET com-
mand initializes any new devices
it finds. If a stream number is
given, then the channel asso-

RESTORE
RESTORE x

RETURN
RUN
RUNx
SAVEf

SAVE f LINE x

SAVE f DATA
SAVE f DATA $0
SAVE f CODE m,n

SAVE f SCREENS
SOUND x,y;a,b,c,d .

STOP
VERIFY

ciated with the specified stream
is reinitialized. The RESET *
command does the equivalent of
turning the machine off and then
on again.
RESTORE

Restores the data pointer to the
first DATA statement in a line
with a number at least n: the
next READ will start reading
there.

Return from subroutine.
RUN0

CLEAR, then GOTO, x.
Saves the program and variables
with their values.
Saves the program and variables
so that, if they are loaded, there
is an automatic jump to line x.
Saves a numerical array.
Saves a character array.
Saves n bytes starting at address
m.

Saves a screen picture.
Sets register(s) to specified val-
ues) in sound generator.
Stop the program.
Like LOAD except that the in-
coming data is not loaded into
memory, but compared against
what is already there. An error is
given if any comparison shows a
difference. All forms as per
LOAD.

September/October 1983 « SYNC

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Table 2. List of Functions.

ABSx
ACSx
x AND y
x$ AND y

ASNx
ATTR (x,y)

BIN x

CHRSx
CODE x$
COSx
EXPx

FREE

INx
TNKEYS

INTx
LNx
NOTx
xORy

Absolute magnitude.

Arccosine in radians.

xifyoO: Oif y=0

x$if y<>: "" if y=0

Arcsine in radians

Attributes for character on screen at

position x,y

Yields the decimal of the binary

number x. (i.e., PRINT BIN

10101010 prints 170).

The character whose code is x.

The code of the first character in x$

Cosine in radians

FN followed by a single letter calls

up a user-defined function.

Returns the number of bytes of

memory available to the user.

Reads the byte at I/O port x.

The character currently being

firessed key.
nteger (in characters) of x$.
Natural logarithm (to base e).
OifxoO; 1 if x=0
1 if b< >0; xifb=0

PEEKx

POINT (x,y)

RND

SCREENS (x,y)

SGNx

SINx
SQRx
STICK (x,y)

STRSx

TANx
USR x

USR$
VALxS

The byte stored in memory location

3.14159265...

1 if the pixel at x,y is ink color; if it

is paper color.

A random number x, such that

0<x<l

The character that appears at

character location x,y on the screen.

Signum: the sign -1 for negative,

for zero or + 1 for positive) of x.

Sine x.

Square root.

Reads stick number y. Reads button

or joystick position according to y.

The string of characters that would

be displayed if x were printed.

Tangent.

Calls the machine language routine

at address x.

The address of the first of eight bytes

describing the bit pattern for a user

defined character.

Evaluates x$ as a numerical

expression.

performs. The TS2000, however, is de-
signed to be able to handle some larger
and more involved tasks. Its cassette inter-
face scheme has been designed to meet,
functionally, with the needs of the system
and its user. The cassette runs at about
1500 bps (bits per second). This means
that the user can save 16K in approxi-
mately 87 secondsl —bout five times fast-
er than the speed of the interface on the
TS1000.

Because of the difference in the actual
hardware interface between the two ma-
chines, TS1000 cassettes cannot be read
into a TS2000 and TS2000 cassettes can-
not be read into a TS1000. The interface
is very reliable. I have been using the
machine for about 10 months by now, 8-
15 hours a day, and I have had perhaps a
half dozen errors while trying to LOAD a
program into the TS2000.

The TS2000 has two connectors avail-
able for adding joysticks (one or two) to
the system. The industry standard 8-

position joysticks connect to the system
via a 9-pin D-type connector. These are
the same joysticks used by Atari and many
other manufacturers.

Bank Switching

The most innovative feature of the
TS2000 is bank switching. This is a means
of expanding the computer's address
space. Through the flexible scheme thai
Timex has designed, the TS2000 has the
ability to access up to 256 * 64K, or 16
million bytes of memory. Is anyone other
than me waiting to see who develops the
"16 megabyte RAM pack" first?

Conclusion

All in all, the TS2000 is a very powerful
system. With the above described and
below detailed features, plus a few extras,
the system packs quite a load at a sug-
gested retail price of $199.95 for the
TS2068 and $149.95 for the TS2048.

In the next "Perceptions" I will discuss

in detail the graphics capabilities and the
memory-expanding bank switching tech-
nique used by Timex to enhance the
functionality of the machine. H

Read This
First

Before you enter the programs in
this issue, please note:

All programs require the 8K ROM
and 16K RAM unless indicated other-
wise at the top of the first page of the
article.

NEWLINE and ENTER are used
interchangeably.

A letter after a number shows the
type: b for binary, d for decimal, and h
for hexadecimal.

In PRINT statements:

# : Enter a necessary space.

A (32): The underline means use
the graphic on that key. The number
in ^) tells how many times.

A: The overline means use the key
in inverse.

INPUT : An underlined word found
on the keyboard should be not be
spelled out. Enter it directly. If it will
not ENTER, hit THEN and then the
keyword you want; backspace, delete
THEN, and continue entering the line.
This memory saving technique may be
disregarded if you have enough RAM.

September/October 1983 « SYNC

hardware tips

Robert D. Hartung

Ed.- A WORD OF CAUTION: Any

hardware project must be approached
with extreme caution. SYNC cannot be
responsible for any problem that may
arise from attempting hardware projects.
Obviously, any damage to your computer
can be costly in time and money. If you
do encounter a problem, write a clear
description of the problem either to
SYNC or to the author and include an
SASE. We will make every effort to find
a solution.

For our "Hardware Tips" department
this time we have asked Robert Hartung
to comment on some letters from our
readers. Since he had only the infor-
mation given in the letters to work with,
he cannot guarantee his answers. Rather
his responses should be regarded as sug-
gestions to help look for the answers. In
most cases more details would be required
in order to give a fuller answer. We
welcome comments from readers on these
problems also.

ROM and RAM
Problems

No Cursor

I added the 8K ROM and 16K RAM
pack to my ZX80. With the 4K ROM/16K
RAM pack, the cursor appears; however,
with the 8K ROM/16K RAM pack, the
cursor does not appear.

James Kinsella

2846 St. Paul Blvd.

Rochester, NY 14611
Comment:

1) Examine the 8K ROM carefully with
a magnifying glass to make sure none of
the pins are loose, broken, buckled, or

Robert D. Hartung, PO Box 125, Palmyra, NY
14522.

bent under or to the side, and that all are
entering properly into their respective
positions in the IC socket, with the notch-
ed end of the ROM to the notched end of
the socket as was the old ROM.

2) Guard against static damage to the
ROM chips. If you do not have a ground-
ing clip for ICs, it is good practice that
the conductive foam wrapper be laid out
next to the IC socket on the PC board
before removing the old ROM from the
socket and the new ROM from the foam.
After gently lifting the old ROM with a
very small screwdriver under each end,
but with all the pins still touching the
socket, place your little finger on the
modulator shield, your middle finger on
the foam, and lift the old IC out with your
thumb and forefinger at each end of the
IC, not touching any pins. Place it on the
foam and pick up the new ROM the same
way. It may be necessary to apply consid-
erable pressure sideways, carefully and
evenly, against all the pins at one side of
the iC in order to line up all the pins on
the other side for proper insertion.

A large (2" or larger) jaw-type paper
clip, such as those made by Esterbrook
and sold for about $1 in larger stationery
stores, makes a good substitute for a
regular IC clip. Connect a grounding
jumper between the clip and modulator
shield and put the clip jaws over the IC
module and on the pins on both sides
before removing the IC from the conduc-
tive foam or prying the old ROM up from
its socket. If properly positioned on the
pins, the clip jaws will compress pin-rows
toward each other for entry into the
socket.

3) Herb Hornung's suggestion in SYNC
2:4, p. 76, may apply.

4) If the computer still does not work
and if the ROM has not been subjected to
static damage in handling after removing

it from the conductive foam, it is possible
that you have received a defective ROM.

Unconnected Input on the RAM Pack

On the Sinclair RAM pack one of the
inputs to IC 2 (7400) pin 10 is not con-
nected to +5V or ground. This is an
unused gate on the chip and could con-
tribute to some RAM pack difficulties.

Rois R. Harder

895 Shakespeare Ave.

North Vancouver, B.C.,

Canada V7K 1E7
Comment:

Sinclair's 1981 schematic for the 16K
RAM shows pin 8 of the 74LS00 going to
pin 1 of IC 3 and IC 4, and pins 9 and 10
of IC 2 both going to RFSH port of the
edge connector.

RAM Pack Connections

The ZX81 performance with the Sin-
clair 16K RAM pack was so erratic that it
was almost impossible to obtain any con-
sistant results. Repeated cleaning of the
contacts resulted in only temporary im-
provement. I have, however, improved
performance immeasureably by a simple
procedure. I inserted a short piece of
copper wire about 1/4" long under each
of the 44 contact fingers on the RAM.
The wire was from two or three one watt
carbon resistors.

P. W. Andrew

4824 E. Grant

Fresno, CA 93727
Comment:

Some later versions of the 16K RAM
pack have greatly increased contact-
finger pressure on the edgeboard con-
nector compared to the earlier models.
This is to accomplish what you seem to
have achieved by wedging them more
tightly to the edgeboard connecting
strips.

September/October 1983 • SYNC

AARDVARK - THE ADVENTURE PLACE
TRS-80 COLOR COMMODORE 24 VIC-20 SINCLAIR/TIMEX TI99

WE CARRY MORE THAN ADVENTURESII

MAXI PROS WORD PROCESSING X^**

The easiest to use word processor that I
know of. Has all the features of a major word
processor (right and left margin justification,
page numbering, global and line editing, single,
double, triple spacing, text centering, etc.) at
a very cheap price because we wrote it in
BASIC. Includes 40 page manual and learning
guide. Easily modified to handle almost any
printer combination. Available on disk or tape
for VIC20, COMMODORE64, and TRS-80
COLOR computer. Requires 13k RAM on
Vic, 16k EXTENDED on TRS-80 COLOR.
$24.95 on tape $29.95 on disk.

LABYRINTH - 16K EXTENDED COLOR
BASIC — With amazing 3D graphics, you fight
your way through a maze facing real time
monsters. The graphics are real enough to
cause claustrophobia.

Similar game for Timex/Sinclair 16k - hunting
treasure instead of monsters $19.95.

ADVENTURE WRITING/DEATHSHIP by
Rodger Olsen - This is a data sheet showing
how we do it. It is about 14 pages of detailed
instructions how to write your own adven-
tures. It contains the entire text of Deathship.
Data sheet - $3.95. NOTE: Owners of TI99,
TRS-80, TRS-80 Color, and Vic 20 computers
can also get Deathship on tape for an addi-
tional $5.00.

Dealers-We have the best deal going for you.
Good discounts, exchange programs, and fac-
tory support. Send for Dealer Information.

Authors -Aardvark pays the highest commis-
sions in the industry and gives programs the
widest possible advertising coverage. Send a
Self Addressed Stamped Envelope for our
Authors Information Package.

ADVENTURES - Adventures are a unique
form of computer game. They let you spend
30 to 70 hours exploring and conquering a
world you have never seen before. There is
little or no luck in Adventuring. The rewards
are for creative thinking, courage, and wise
gambling — not fast reflexes.

In Adventuring, the computer speaks and
listens to plain English. No prior knowledge
of computers, special controls, or games is re-
quired so everyone enjoys them— even people
who do not like computers.

Except for Quest, itself unique among Ad-
venture games. Adventures are non-graphic.
Adventures are more like a novel than a comic
book or arcade game. It is like reading a par-
ticular exciting book where you are the main
character.

All of the Adventures in this ad are in Basic.
They are full featured, fully plotted adventures
that will take a minimum of thirty hours (in
several sittings) to play.

Adventuring requires 16k on Sinclair, TRS-
80, and TRS-80 Color. They require 8k on OSI
and 13k on VIC-20. Sinclair reauires extended
BASIC. Now available for TI99.

TREK ADVENTURE by Bob Retelle - This
one takes place aboard a familiar starship and
is a must for trekkies. The problem is a famil-
iar one - The ship is in a "decaying orbit"
(the Captain never could learn to park!) and
the engines are out (You would think that in
all those years, they would have learned to
build some that didn't die once a week). Your
options are to start the engine, save the ship,
get off the ship, or die. Good Luck.

Authors note to players — I wrote this one
with a concordance in hand. It is very accurate
— and a lot of fun. It was nice to wander
around the ship instead of watching it on T.V.

DERELICT by Rodger Olsen and Bob Ander-
son — For Wealth and- Glory, you have to ran-
sack a thousand year old space ship. You'll
have to learn to speak their language and
operate the machinery they left behind. The
hardest problem of all is to Jive through it.

Authors note to players — This adventure
is the new winner in the "Toughest Adventure
at Aardvark Sweepstakes". Our most difficult
problem in writing the adventure was to keep
it logical and realistic. There are no irrational
traps and sudden senseless deaths in Derelict.
This ship was designed to be perfectly safe for
its' builders. It just happens to be deadly to
x alien invaders like you.

Dungeons of Death - Just for the 16k TRS-
80 COLOR, this is the first D&D type game
good enough to qualify at Aardvark. This is
serious D&D that allows 1 to 6 players to go
on a Dragon Hunting, Monster Killing, Dun-
geon Exploring Quest. Played on an on-screen
map, you get a choice of race and character
(Human, Dwarf, Soldier, Wizard, etc.), a
chance to grow from game to game, and a 15
page manual. At the normal price for an Ad-
venture ($19.95 tape, $24.95 disk), this is a
giveaway.

PYRAMID by Rodger Olsen - This is one of
our toughest Adventures. Average time
through the Pyramid is 50 to 70 hours. The
old boys who built this Pyramid did not mean
for it to be ransacked by people like you.

Authors note to players - This is a very
entertaining and very tough adventure. I left
clues everywhere but came up with some in-
genous problems. This one has captivated
people so much that I get calls daily from as
far away as New Zealand and France from
bleary eyed people who are stuck in the
Pyramid and desperate for more clues.

MARS by Rodger Olsen - Your ship crashed-
on the Red Planet and you have to get home.
You will have to explore a Martian city, repair
your ship and deal with possibly hostile aliens
to get home again.

Authors note to players — This is highly
recommended as a first adventure. It is in no
way simple— playing time normally runs from
30 to 50 hours - but it is constructed in a
more "open" manner to let you try out ad-
venturing and get used to the game before
you nit tne really tougn proDiems.

QUEST by Bob Retelle and Rodger Olsen -
THIS IS DIFFERENT FROM ALL THE
OTHER GAMES OF ADVENTURE!!!! It is
played on a computer generated map of
Alesia. You lead a small band of adventurers
on a mission to conquer the Citadel of Moor-
lock. You have to build an army and then arm
and feed them by combat, bargaining, explora-
tion of ruins and temples, and outright ban-
ditry. The game takes 2 to 5 hours to play
and is different each time. The TRS-80 Color
version has nice visual effects and sound. Not
available on OSI. This is the most popular
game we have ever published.

32K TRS 80 COLOR Version $29.95.
Adds a second level with dungeons and
more Questing.

PRICE AND AVAILABILITY:

All adventures are $19.95 on tape. Disk
versions are available on VIC/COMMODORE
and TRS-80 Color for $2.00 additional. $2.00
shipping charge on each order.

Please specify system on all orders

ALSO FROM AARDVARK - This is only a partial list of what we carry. We have a lot of other games (particularly for the
TRS-80 Color and OSI), business programs, blank tapes and disks and hardware. Send $1.00 for our complete catalog.

AARDVARK

2352 S. Commerce, Walled Lake, Ml 48088 / (313) 669-31 10 ^gk

Phone Orders Accepted 8:00 a.m. to 4:00 p.m. EST. Mon.-Fri.
TRS-80 COLOR TIMEX/SINCLAIR COMMODORE 64

$2.00 shipping on each order
1-800-624-4327

CIRCLE 1 ON READER SERVICE CARD

VIC-20

RAM Pack Crashes

Until recently I have had no problem
with my ZX81 with the RAM pack at-
tached. Now the computer crashes while
I am typing in a problem. The screen
goes blank and the program is erased.
After unplugging and plugging it in again,
it works fine for 10-15 minutes. I have
taped the RAM pack securely in place so
it cannot move. I do not think the prob-
lem is overheating because sometimes it
will work for an hour or two before crash-
ing, but other times it will crach almost
immediately after running.

Brent Helms

5411 SW 96 Ave.

Miami, FL 33165

Comment:

Should a Sinclair 16K RAM pack that
works well on an ZX80 with the 8K ROM
have any problems on a TS1000? Mine
operates 5-6 minutes and then the screen
fills with garbage and eventually flops
over full of curved lines.
Jim Mahoney

RD 4, Box 247

S. Salem, NY 10590

Comment:

Both of these situations may be caused
by a combination of overheating and

edgeboard connection problems.

The overheating can best be solved
with an external voltage regulator (see
SYNC 3:2, p. 68). Since the regulator
requires nearly 2V offsetting voltage,
some ZX/TS power supplies may not
provide the 9V output under load re-
quired for SAVE mode on some ZX/TS
computers.

However, by substituting a DPDT
switch for the SPST shown in the SYNC
article and connecting the regulator input
to lug 1 of the first set of switch-poles and
the regulator output to lug 2 (C) of this
first set of poles, the external regulator is
shunted out of the circuit for full voltage
in this switch position which is used in
SAVE mode. For the 7V output used for
cooler operation in all other modes than
SAVE, connect the regulator GND term-
inal (3) to lug 2 (C) of the second set of
switch poles and connect a 330 resistor
in series between lug 3 of this second set
of poles and ground (-). The shunt resistor
is omitted. Do not use this configuration
with power sources greater than 13
WVDC.

The edgeboard connector problems
can occur because of oxidation of the
soldercoating on the connector strips
even when mechanical stability has been
secured. Swab both sides of the connector

strip liberally with TV contact cleaner/
lubricant and slide the RAM pack on and
off several times. Insert the pack fully,
then back it off just enough that the
contact fingers are not pried open by
pressure of the pack case against the
computer case.

RAM pack wobble may be prevented
in various ways: 1) Mount both the com-
puter and the RAM pack on a flat mount-
ing board (3/4" chipboard is fine) with a
bit of picture-mounting tac-dough under
each corner of the computer and under
the RAM pack legs will ensure they do
not move relative to each other. 2) Some
have had success also by putting extra-
high pads under the computer so that the
RAM pack hangs free from the con-
nector. 3) Ribbon-cables with connectors
on each end also work well. 4) Hard-
wiring and placing both the RAM pack
and computer inside a grounded metal
cabinet as used with some keyboards is
the best approach of all.

New Pads

My answer to RAM pack wobble was
to get some sticky pads at Radio Shack
(1/2" in diameter by 1/8" thick) to replace
the standard pads. At the keyboard end I
put 2 pads 1/2" closer to the expansion
port. At the port end, they are 1/2' O.C.

TIMEX IS HOW

20%0FF.

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-^^MWAssetM,^

Vucalc H —

JjnwntonTcirtriP — — —

*!*?l£caimr

___ftes|derrt^ — —

logger — —

Gambler

__AndMw7TT — — ■

3*«S0CMTKn«p

—H^^^rCJTs

J?«!eflMejMe7~^

J^jMAnaiyzir

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J* J 5!!!fMnal^iP —

9.95
~~ttJS~

1^95^
J^95^

Discount

~J5^96~
^T96~

M. 9.95
9.95

THE COMPUTER, THE PRINTER, THE SOFTWARE, THE POWER.

Why pay more and get less? A. + Associates now carries the
complete line of TIMEX hardware and software at a 20% dis-
count. Who else can make that claim? If you are interested in a
computer, a printer or just software from the company that
designed the computer, then look no further. We have it.
Among our specials are Printers at $79, RAM Packs $39, and 3
rolls of paper $5 (All shipping included). Inquire about the
1500, 2000, and our Three for Two program offer.

Call us at (312) 991-5285 for a list of titles and products or
write: A. + Associates, 175 Fifth Avenue, Suite 3119 NYC
10010. To order a title listed here, send a check or money order
with a note indicating selection plus $1 postage /handling, .50
for each additional program. Illinois and New York State
residents please add sales tax. Orders shipped immediately.

A. ^Associates

NEW YORK / CHICAGO

CIRCLE 2 ON READER SERVICE CARD

NOW

YOU CAN HAVE

ALL THE ANSWERS

With the most complete Sinclair software library available.

CXS1ZX0OZX81

UNDERSTANDING YOUR ZX81 ROM

by Dr. Ian Logan

SYNC Magazine said: "SYNC readers will recognize
Dr. Logon as a major ZX80/81 expert whose writings
are wdl worthwile. Understanding Your ZX81 ROM is
no exception. The book falls logically into five ports:
o brief review of the Z80 CPU, next a quick intro-
duction to the internal arithmetic and number base
manipulations; o discussion of the Z80 machine code
instructions grouped by function; a detailed exam-
ination of the relevant parts of the 8K ROM; Dr Logan
introduces machine code programming by treating it
os an extension to Basic; and complete listings of the
more important 8K ROM routines are given as well os
the usual tobies of machine code language
instructions, decimal-hexadecimal conversions, and
keycodes. Understanding Your ZX81 ROM should be
high on your list." Now available for only $14.95

MACHINE LANGUAGE PROGRAMMING
MADE SIMPLE

Michael Roberts, SYNTAX Magazine wrote:
"I wanted to review this book because I'm the person
it was written for I taught myself BASIC and con
now do most of the things I want to with it. I felt that
Machine Language would be a good addition to
speed up some programs and improve display. The
idea of Machine Language made simple' appealed
to me. It's the best explanation of Machine Language
for Machine Language beginners I've seen.

Its friendly style is painless reading
analogies help make this languag
This introduction is a must " Now a
only $14.95

NOT ONIY 30 PROGRAM

is a collection of programs for

ZX81 /TS1000 Not only Bottle

Blackjack, Wall Breaker, Mini/ • ^O^i

1 K Draughts, but also each d ^_ °></

programming hints, space y fi'^Al s

PEEK and POKE explaine.

ZX Computing said "Th

*A '"to Si

Now available for only
THE COMPLETE TIMEX i
ZX81 ROM Disassembly^

Dr. Logan and Dr Frank O'Hcm i *rw« Q*omtn0O
all routines in the ROM and comment on eo'cwSfljj^'?;
This book is a must for the experienced programmer
L'Ordtnateur Indivtduel (the leading French personal
computing magazine) said: "Dr. Ian Logan has
disassembled the 8K monitor program of the ZX81 /
TS1000 For those who want to write programs in
machine language, it is PART A which is the more
interesting, because it contains the majority of BASIC
commands, while Port B is far more technical,
comprising essentially of the ZX81 /TS lOCXTs floating
point calculator. In conjunction with Understanding
Your ZX8J ROM this book allows anyone well

for S34.5CT

cassettes ore also avoi

to*.

:?ooo

new n

^flighty."
i« available

<<* $7.50

Plus

award winning

software!

orders to MELBOURNE HOUSE SOFTWARE INC.
Dept CS 347 Reed wood Drive. Nashville. TN 37217

TAPES:

n 13941 Gamestape 111 Programs-IK $14 95

13942 Game-nape 2 3Games-16K $14 95

13943 camestape 3 Catacombs

Adventure -16K $1495

I 13944 camestape4 3D Monster Maie-16K $1495

I i 13945 Camestapes 3DOrblter-l6K $1495

26446 Space Trek 16K $14 95

26359 Super invasion -1K $14 95

26318 Wall Busters IK $14 95

26472 10 Exciting Programs -1K $14 95

I i 26284 Reversl-1K $1495

26406 Toolbox -IK $14.95

26490 Basic Course 2 cassette pack $7 50

14026 Combat Hlght-16K $14.95

Enclosed Is my check or money order for $
please charge my visa or Mastercard

Signature

Address

visa and M/C orders

can be phoned In: 615/361-3738

Dealer orders and queries: 800/251-5900
(ask for a Melbourne House operator)

BOOKS:

25895 The Complete Basic course
25957 Machine Language Programming

Made simple
20922 The Complete Tlmex 'Sinclair

ROM Disassembly
26025 Not Only 30 Programs
25913 Understanding Your ZX81 ROM
Q 51539 ins and Outs of the Tlmex

TS1000

TOTAL

Residents of CA. MD. TN. please add sales taxes
Add $2 for Shipping l Handling, foreign orders add $6

$34 50

$14 95

$1995

$9 95

$1495

$1295

SYNC7

TOTAL: $„

card*

expiration date

Name

^aty

State

zip

MELBOURNE HOUSE SOFTWARE «kW

CIRCLE 43 ON READER SERVICE CARD

INTERFACE
JOYSTICK
Interlace to use 2 joy-
sticks with the ZX-8I
games Work instructions
detailed to prepare their
own programs controlled
by loystick and to adapt
the ones already existing
to be controlled by joy-
sticks S39

Sinclair Pla

HARDWARE Qua** com

portents ■ Strictest Quality O

the industry assure the very Best lor

KOurZXSI TIMEX 1000

ALL FROMO/W MANUFACTURER

MEMORY

EXPANSIONS

Highest Technology and
gold plated connectors
for unbeatable results All
Piggy back port tor other
add-ons and LED indi-
cator

16 K = S54

32 K S95

64 K = S135

OS SOUND GENERATOR

integrating the AY-38910 chip with 16 internal records 3
independent tone generators Scale ot 5 octaves Led ,o
inform when the „»„»...„. ... Slaves Lea to

ometer and amplifier output

RIBBON CONNECTOR
Extends the ZX-at BUS to avoid
failures in the memory and peri-
pheric connection. s 1 9

, CENTRONICSINTERFACE
.+ Interface to connect the ZX-81 to a serial printer
which can work under this norm $69

* PRINTERCABLES16

INTERFACE FLOPPY DISK (SUGAR)

Based on standard unit of 5' 4 with controller

interface It has 43 K bytes of storing Possibility

rn^Tn 9 T "" Pr °9' ams to«*ng m less
than 20 seconds $ 1 1 5

PROFESSIONAL KEYBOARD

52 keys -Fully assembled No soldering Outlets to- MIC EAR

TV «lc o„„

S89

PROGRAMMABLE

CHARACTER

GENERATOR
Allows to program 128
new graphic characters
It has 1 K RAM to store
them Switch ON/OFF
10 select new charac
lers or Sinclair charac-
ters S45

ce Presents

SOFTWARE oucksivas

! atest bits make your ZX81 TIMEX
'000 give you me best m exciting
entertainment and fun

CROAKA
CRAWLA

SUBSPACE STRIKER

It comes from out of nowhere and
then vanishes back into the ether
With your deadly antimat torpe-
does, you unleash havoc in the
Federation's Spacelanes
Plus Zor battle of the robots.

SUBSPACE
STRIKER

f*l

MUNCHESS

PIONEER TRAIL S12

Authc Marlon Stubbs
A Western adventure Featuring
20 levels of play Mind Game
plus shooting rifle speed uses all
keys and is measured against the
players personal average respon-
se This game is based on histo-
rical data

CROAKA CRAWLA $12

Author John Field
It's not easy being a frog what
with the trucks and lods. the cro-
codiles and turtles The continual
battle for survival, struggle with
the universe ... Us frogs do some-
times get a little carried away,
see you on the far bank.
Special Features: Flies, croco-
diles. Sinking turtles. Inverted
logs. Progressive difficulty attack
waves.

GALAXIANS
& GLOOPS

MUNUHtSS S12

Author A. Laird

Beware the Munchees. a board

creaks in the time lost corridors.

A ghostly presence, a rush of

wind, a forgotten echo whispering

around the house and following

chuckle of ghosts rolling forward

on cold breezes

Special Features: Ghostly ghosts.

pills and fruit, munchy munchees

TRADER

SCRAMBLE

GALAXIANS & GLOOPS

Author: T. Beckwlth
The peaceful Fragnn battle the
large Wobbly Galaxian birds with
a device built of dragon gut and
with small furry bombs. Splach,
Ploof.Splach, Ploof. Tank. Ploof
A keen eye and a fast hand help
Special Features: Two types of
swooping, bombing, galaxian. All
fully adjustable

GLOOPS: An amazing maze gaj

OS SCRAMBLE

Author: Dave Edwards

A landscape of r
teaus and vaflies
ship as waves ~*
firing fror
up from
expla-""

' -^ 1

■%^^e^/

•^ W ev

1 njgPj^ji

~ ,1M ™

<a^Lfl^Z

TRADER

A trilogy of 16 K programs mat c give an epic 48K

graphic adventure As a galactic trader, you deal with some very

bizarre customers indeed Will you live to ten the tale

It is hard enough to look at an amorphus hydrosihcon blob from

Psi. never mmd swing a dea m\t\ one But when tne_/ ask to pick

your brains do you real'/ know »ha1 they havt in mmd ">

As an mtergaiactic door to d00' salesman, you do the rounds of

the Moons od Mermen a beautiful gas giant m the Aitair system

n tarin i ne -ire is tougn me bargaining
hard You can gam fame and fortune or end up spaced out in a
Deltan hellhole

You deal m Synthomunch and Boosterspice.

Gold You meet other ex-Terrans and uni

res You go gravity diving in your little spacehoope' Pegasus

and have to land on a solid chunk of Uranium to pick up fuel

All Software Available
SPANOL

Sinclair Place
P.O. Box 2288
Redmond, WA 98052

Phone: (206) 483-1730

□ AMERICAN EXPRESS

□ VISA

□ mastercard

□ cheque/p.o. Name
Address

CALL TODAY TOLL FREE

F>>^ n^s r\r% r\ fy r\^\ r\r\ r\ r*

r yt Mail: Sinclair Place

^ t

* •**••***!

PC P.O. Box 2288

Redmond, WA 98052

^jTy

ITEM

PRICE

TOTAL

SHIPPING and HANDLING

4.00

TOTAL $

CIRCLE 41 ON READER SERVICE CARD

21st CENTURY ELECTRONICS

RQ-IT DHI W CTRPFT

GUTTENBERG N.J. 07093

(201)869-2616

Hardware

DISK INTERFACE

$189.95

PERTEC DRIVE

$225.00

POWER SUPPLY

$ 89.95

XEROX CASE

$ 49.95

64KRAM

$149.95

16K RAM

$ 49.95

HI RES PACK

$ 99.95

PRINTER N INT

$399.95

EZ-KEY KEYBOARD

$ 84.95

HUNTER BOARD

$ 59.95

FORTH BOARD N DOC.

$ 49.95

SEE THRU INT. COVER

$ 14.95

VU MONITOR

$ 19.95

STARTING FORTH BOOK

$ 22.00

UHF MODULATOR

$ 15.00

BMCMONITER

$109.95

MONITER CONVERSION

$ 15.00

MONITER SWIVEL STAND

$ 39.95

TIMEX/1000

$ 49.95

TIMEX/1500

$ 79.95

TIMEX/2048

$199.95

TIMEX PRINTER

$ 89.95

21st CENTURY ELECTRONICS
Business Series

A— SALESDATA2E $34.95

16K complete sales storage and
analysis report for up to 30 customers
for a quarter year. Comes in a book
form with a master tape and 2 blanks,
and complete forms documentation. A
hard copy can be made of all the
reports.
B— FILEDATA2E $20.95

16K not only files names, addresses,
zip, telephone no., but allows you 2
lines of comment per entry. It contains
an alphabetical sort and allows you to
change any part of any entry. A hard
copy can be made of the complete
entry or just the mailing address. All
Series 2E programs come with full
documentation.

C— PAYDATA 2E $34.95

16K complete payroll program for 25
people. Includes hard copy mode for
pay stubs, and accountant information,
automatic overtime calculations for
over 40 hrs., and all federal tax deduc-
tions are set in the program. There are
also instructions allowing you to set
your own state taxes. All Series 2E
programs are user friendly.

CIRCLE 72 ON READER SERVICE CARD

Books and Software

THE SINCLAIR ZX81

$12.95
$00.00

PROGRAMMING FOR
REAL APPLICATIONS

ZX-81 /TIMEX

$ 9.95

BASIC AND MACHINE
PROGRAMMING

$00.00

STARTING FORTH

$18.00

BYLEOBRODIE

$00.00

STARTING FORTH

$22.00

HARDCOVER

$00.00

MOTHERSHIP

$16.95

BIORHYTHMS

$14.95

SUPER CHESS

$19.95

MASOGS

$12.95

FINANCIAL MANAGER

$16.95

THEGAMBLER

$14.95

FLIGHT SIMULATOR

$17.95

CHECKBOOK MANAGER

$15.95

THEFROGGER

$17.95

UNDERSTANDING BASIC

$15.00

SALES FILE 16K

$19.95

SALES FILE 64K

$19.95

INVENTORY 16K

$ 9.95

INVENTORY 64K

$ 9.95

from the edge of the computer. On the
other axis they are in line with the
originals.

Andreas Rainwater

Rt. l,Box57-A

Coyle, OK 73027

Screen Display
Problems

RAM Pack Buzzing Sounds

Raymond Fowkes in SYNC 2:4 sug-
gested soldering two foil tabs on the
underside of the PC board together with
a short piece of wire to solve the problem
of the buzzing sounds caused by the 16K
RAM pack. Is this safe for the computer?
John Torrance
41 Alpine Pl._
K.earny, Ni 0/032
Comment by Raymond Fowkes:

I learned that there was more to the
story after I wrote to SYNC. My ZX81
was a kit, and it seems that Sinclair left
out the instructions for installing the long
thin metal grounding strap in the com-
puter (not the RAM pack as a few
thought). This raised the resistance in the
volt trace just enough to cause noise
when the extra load from the RAM pack
was added.

Therefore, anyone who does not have
a long thin silver strip of metal running
across the noncomponent side of the
ZX81 may solder a wire to the two large,
pads of bare foil (labeled TB in Figure 2)
on the underside of the PCB. One is next
to the edge connector where the RAM
pack is attached; the other is in the oppo-
site corner next to the regulator (the 3-
prong IC on the component side with the
big metal heatsink). Factory assembled
units should be OK in this respect, but
those with hardware experience who are
very careful could further reduce the
noise by connecting wires in parallel with
other traces, especially the one carrying
5V to the edge connector though this is
not advised because of various risks.
Comment:

I referred the above question to
Raymond Fowkes for clarification. I note
from letters by owners of factory built
ZX81s that some may have defective
solder connections on this strip or else it
may not be making proper contact with
the metalized coating inside the case. The
result is increase TV1, which the 16K
RAM pack may raise to an even higher
interference level. The solution is to make
sure that all the solder connections are
secure by reheating them and ensure that
the strip is making contact with the case
by arching it slightly higher above the
board in the center. However, this will
not cure the noise which originates in the
voltage converter in the RAM pack itself.
This feeds back transient noise into the

September/October 1983 « SYNC

computer power line as well as radiating
RFI if all the grounding strips in the RAM
pack are not making proper contact with
the metalized coating in the case. Some
16K RAM packs, such as Memotech, do
not use this power conversion and so
produce less RFI.

The solution involves the adding of
suppression around the Zener diodes
which originate the most of this noise,
but, unless the proper components are
identified, the RAM could be disabled. A
thin metal box formed to fit over the
RAM case and grounded to the TV mod-
ulator case (but not touching the edge-
board connector) will alleviate the RFI
which affects the TV display. Heavy alum-
inum foil may be used. (See Bruce Kirk's
letter.)

Bsrk Bands snd Noise

The 16K RAM from Apropos Technol-
ogy worked well on my ZX80 except for
considerable noise in the TV display. By
covering the ZX80 and module with alum-
inum foil grounded to the coax to the
TV, I reduced the noise. However, when
I used the 16K on the TS1000, two darker
horizontal "bands" appeared in the TV
display, moving slowly and evenly down-
ward. The display itself (symbols and
spacing) was not affected although these
bands overloaded the TV sync and caused

minor "tearing" of the picture.
Bruce P. Kirk

RR 4, Box 4033 B
La Plata, MD 20646
Comment:

Your "fix" of the noise problem with
the foil shows the need for more adequate
shielding in the RAM pack case unless
the noise source is corrected by suppres-
sion at the internal power converter of
the RAM.

The moving horizontal bands in the
TV display may be partially from trans-
ients going back into the computer along
the 9V bus from this power converter
noise. Usually such bands indicate inad-
equate filtering of the DC power supply.
This may easily be corrected by connect-
ing a 2200 uF 35WVDC capacitor be-
tween the DC power cord leads. However,
the loss of TV sync and tearing may
indicate a combination of kH, noise
transients on the power bus of the com-
puter, and excessive ripple in the power
input. You may have to work on these
one at a time.

RFI Trash

The RFI trash on my portable TV
screen is very annoying. However, on my
17" TV the screen is crystal clear. What
does my large TV have that my small one
does not? Is there a circuit I can build for

OBOOIcliRS

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CIRCLE 65 ON READER SERVICE CARD

my small set to solve the problem?

Rick Goulian

1525 N. Euclid, Apt. 121

Tucson, AZ 85719
Comment:

The tuning section and selectivity of
the 17" TV may be better or have better
shielding. Some TVs are designed for
better RF harmonic rejection than
others.

1) Be sure that the built-in antenna or
rabbit-ears are completely disconnected
from the TV input terminals and discon-
nect the CATV or other antenna leads.
Relocate them and the TV power cord
and the computer power cord as far as
possible from each other.

2) Sometimes it helps to put 2 or 3
ferrite sleeves on both these power cords,
respectively, as near the TV and the com-
puter as possible. Wind the cord through
the hole several times. (Radio Shack has
assorted packages.)

3) The length of the cable between the
computer and the TV may be critical
with some tuners. The 48" length supplied
with the computer is designed to be one-
fourth wave-length at the pix frequency
of TV channel 3 for maximum signal-
transfer to noise ratio. The TV/computer
switch box supplied lengthens this enough
to provide a match for TV channel 2, in
length and in impedance. Clean the switch

contacts by spraying TV contact cleaner/
lubricant liberally inside the box and
working the switch back and forth.

4) Some 16K RAM packs emit exces-
sive RFI back to the computer and also
as radiation. Use the computer only on a
non-metallic desk or table, or place it on
a sheet of heavy foil grounded to the
outer conductor of the TV cable plug or
to the TV modulator case. It may help to
fold the foil up and around the RAM
pack also. (See Bruce Kirk's letter.)

5) When severe TV interference oc-
curs, either from RFI from the computer/
peripherals or from being in a strong sig-
nal area on the channel used by the VHF
modulator or on an adjacent channel, the
only real solution may be to replace the
VHF modulator with a UHF modulator
(see SYNC 3:1, p. 72). Try adding a short
patch cable (4-6") to the existing TV cable
if the UHF signal to the TV seems to be
down.

6) Another solution is get a well-
shielded cord for connecting the com-
puter to the TV.

A ZX81 and an 18 year old Sony

My ZX81 kit works only with my 18-
year old Sony portable TV. It works best
with the gain control turned down. With
other TVs the ZX81 seems to be putting
out too much signal and overdrives the

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screen resulting in an unusable, cross-
hatched pictures. I have tried turning
down the AGC on several TVs as well as
a different TV/game box to no avail.

Ross A. Rainwater

305 Regal Dr.

Lawrenceville, GA 30245
Comment:

The cross-hatching would indicate the
problem is RFI rather than overdriving,
which in effect is superimposing one or
more spurious signals to the TV over the
top of the desired one. The Sony gain
control apparently reduces these other
signals enough that only the legitimate
one is visible in the display. Some TVs
have better front-end shielding and selec-
tivity and adjacent-signal-rejection than
others, which may account in part for the
difference in those you have tried.

Small coupling trim-pad capacitors
placed in each side of the TV lead-pair in
the TV/game switch box might help tune
out and attenuate the unwanted signals.
Drill small holes in the box directly over
the trim-pads so they can be adjusted
with the box closed, using a non-conduct-
ing tool.

A better solution, however, would be
to prevent or shield off as much of the
interference as possible at the source.
See above for suggestions for RFI
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CIRCLE 3 ON READER SERVICE CARD

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David Grosjean
David H.Ahl

Making Borders and a
Bouncing Ball

David Grosjean

We will begin our series on compar-
ative programming with the Panasonic
JR-200, the Vic-20, and the TS1000.
Our first exercise is to develop step by
step the routine for creating a border
around the screen and then vary its
dimensions. Our second exercise is de-
velop a routine for a bouncing ball. Both
exercises are useful in certain types of
games.

Making Borders

Our first exercise is easy on the JR-
200 and TS1000 because they have the
PLOT command, while the Vic-20 does
not. First, let's look at the PLOT
command.

On the JR-200, the X axis is along the
top (from to 63), and the Y axis is
down the left (from to 47). On the
TS1000, the X axis is along the bottom
of the screen (from to 63), and the Y
axis is up the left side (from to 43).

Let's PLOT a single point at the cen-
ter of the screen. Notice that a rather
complicated method of cursor move-
ment is the simplest method for the Vic,
while the JR-200 and TS1000 use the
easier PLOT command.

JR-200: TS1000:

PLOT 31,23 PLOT 30,21

VIC-20;

5 PRINT ' '#■ '
1 FOR 1=1 TO 11
20 PRINT ' '####' ' ;
30 NEXT I
40 PRINT ' '###' '

Line notes for the Vic:
5: The control character is a clear
screen character.

10: The control characters in the

September/October 1983 ® SYNC

quotation marks are: reverse on, cursor

right, cursor down, reverse off.
40: The control characters are: reverse

on, one space, reverse off.

To light up this point without any

other printing on the screen, use these

short programs:

JR-200: TS1000:

10CLS 10CLS

20 PLOT 31,23 20 PLOT 30,21
30 GOTO 20 30 GOTO 20

To the Vic version above, add 50
GOTO 50. This does not keep printing
the point over and over again, out it does
avoid printing on the screen.

Now, how can we expand this one
point to a whole line? One way would be
to use a series of PLOT statements. For
example:
JR-200: TS1000:

10CLS 10CLS

20 PLOT 1,23 20 PLOT 1,21

30 PLOT 2,23 30 PLOT 2,21

40PLOT3.23 40PLOT3.21

• •

640 PLOT 63,23 640 PLOT 63,21
Obviously, this is very inefficient and
cumbersome. We could use a FOR-
NEXT statement instead:
JR-200: TS1000:

10CLS 10CLS

20 FOR X=0 TO 63 20 FOR X=0 TO 63
30 PLOT X, 23 30 PLOT X, 21

40 NEXT X 40 NEXT X

50 GOTO 20 50 GOTO 20

Vic-20:
5 PR I NT ' ' # ' '

10 FOR 1 = 1 TO 11

20 PRINT ' '###' ' ;

30 NEXT I

40 FOR 1=1 TO 22

50 PRINT ' '###' ' ;

60 NEXT I

70 GOTO 70

Line notes for the Vic:

5: Control character is to clear screen.

20: Control characters are: reverse on,
cursor down, reverse off.

50: Control characters are: reverse on,
one space, reverse off.

These programs simply draw a hori-
zontal line and, when finished, draw it
over and over again.

As long as we are varying X from the
left to right of the screen, why not draw
two horizontal lines at once, one at the
top and one at the bottom? Here are the
programs to do this:
JR-200: TS1000:

10CLS 10CLS

20 FOR X=0 TO 63 20 FOR X=0 TO 63
30 PLOT X 30PLOTX.0

40PLOTX.47 40PLOIX.43

50 NEXT X 50 NEXT X

60 GOTO 20 60 GOTO 20

Vic-20:

On the Vic, drawing one line using
cursor movement is fairly easy, but
when you get into more than that, it is
easier to POKE into the screen memory.
From now on, we will only use POKE.
In the following program, SM is the
start of screen memory, and the control
character in line 10 is the clear screen
control character.

In lines 40 and 50, the second POKE
command POKEs into the color mem-
ory. This is to insure that what you
POKE into the screen memory is not the
same color as the background. Now that
we are POKEing, there are no X,Y co-
ordinates; each space on the screen is
numbered consecutively, so our equa-
tions for the correct display must

change.

10 PRINT ' '#' '

20 SM=7680

30 FOR I =0 TO 21

40 POKE SM+I , 160: POKE 3

8400+I , 2

50 POKE SM+484+I , 160:PO

KE 38884,2

60 NEXT I

But we want to have vertical borders,
too. We can use the same loop by adding
two more PLOT statements.

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JR-200:

10 CLS

20 FOR X=0 TO 63
30 PLOT X,0
40 PLOT X.47
50 PLOT 0,X
60 PLOT 63.X
70 NEXT X
80 GOTO 20

TS1000:

10 CLS

20 FOR X=0 TO 63
30 PLOT X,0
40 PLOT X.43
50 PLOT 0,X
60 PLOT 63.X
70 NEXT X
80 GOTO 20

But a value error occurs in line 50 be-
cause X exceeds the maximum Y value
that can be plotted. This can be fixed
easily be adding a line before 50 to test
for a value of X over the maximum.

JR-200: 45 I F X>43 THEN 70
TS1000:4 5 IFX>47 THEN GOTO 70
This final program is one of the
shortest ways to draw a border. Of
course, if you are using this routine in
another program, you would not need
line 80.
Vic-20:

On the Vic letting the overflow mis-
take occur as on the other machines
would be too risky to the program in
memory because we are POKEing.
Therefore we must add the overflow
checking line (line 45) before we make a
possibly disastrous mistake. Several
times while we were developing this rou-
tine, we completely lost control of the
computer and simply had to turn it off
and on again. Needless to say, this re-
quired much retyping. (If you are writ-
ing your own program, you cannot write
the test line first; you must do it through
testing.)

10 PRINT ''#• '
20 SM=7680
30 A=4

40 FOR l=0 TO 22
45 IF l>=22 THEN 70
50 POKE SM+I , 160 : POKE 3
8400+I ,A

60 POKE SM+I +484, 160:PO
KE 38884+I ,A

70 POKE SM+I *22 , 160: POKE
38400+I «22, A

80 POKE SM+ I • 22+21 ,160:
POKE 38421+1 *22 , A

90 NEXT I
100 GOTO 100

On the JR-200, color can be added
easily by adding a line 5. Try these:
5 COLOR 1
5 COLOR 3 , 5
5 COLOR 2,6,3

To add a variety of color to the Vic,
change line 30 to:

30 A=INT(7*RND(0) )
In the previous program, instead of
having the border print at the edges of
the screen, it is possible to let the non X
value vary. We will let the distance or
increment from the edge of the screen be
I. The value of I can be used as the co-

ordinate for the top and left side; how-
ever, the right side must be defined as
63-1 (JR-200 and TS1000) and the bot-
tom as 47-1 (JR-200) or 43-1 (TS1000).
This program uses these relationships
to draw a series of concentric borders
which start at random points in the up-
per left quarter of the screen. Note that
the test to see if the maximum Y value
has been exceeded is changed somewhat.
Can you explain why?
JR-200:
10 CLS

20 RANDOMIZE
30 l=INT(23«RND(0) )
40 COLOR ( INT(8«RND(0) )
50 X2=63-l
60 Y2=47-l
70 FORX=l TOX2
80 PLOTX, I
90 PLOT X.Y2
100 IF X2-X<=16 THEN 130
110 PLOT I ,X
120 PLOT X2.X
130 NEXT X
140 GOTO 30
TS1000:
10CLS
20 RAND

30 LET l = INT (RND-22)
50 LETX2=63-I
60 LET Y2=43- I
70 FOR X=l TOX2
80 PLOTX, I
90 PLOT X,Y2
100 IF X2-X<=20 THEN GOTO 130
110 PLOT I ,X
120 PLOTX2.X
130 NEXT X
140 GOTO 30

Again, since we are not using a co-
ordinate system on the Vic, the equa-
tions to figure out the parameters of
each border are different from the equa-
tions of the TSIOOO and JR-200. Can
you figure out how the equations work?
Tip: lines 100 and 110 draw the hori-
zontal lines. CM is the start of color
memory; SM is the start of screen mem-
ory; B is a random color; I is a random
starting point for the borders. Remem-
ber also that the Vic screen is 22 by 23 (0
to 21 and to 22).
10 PRINT ' '#• '
20 SM=7680
30 CM=38400
40 l = INT( 1 1*RND(0) )
50 B=INT (8«RND(0) )
60 X2=21-l
70 Y2=22- I
80 FOR X=l TO Y2
90 IF Y2-X<=1 THEN 120
100 POKE SM+ I • 22+X ,160
:POKE CM + I *22+X,B
1 1 POKE SM+Y2 -22+X ,160
:POKE CM+Y2«22+X,B
120 POKE SM+X*22+I ,160:
POKE CM+X-22+I ,B
130 POKE SM+X*22+X2 , 160
:POKE CM+X«22+X2,B
140 NEXTX
150 GOTO 40

Making a Bouncing Ball

Our second exercise is a simple one
for the JR-200 and TSIOOO: to produce a
ball that bounces off the borders of the
screen. At this point, we will deal only

with the JR-200 and TSIOOO since the
method for doing this on the Vic is
vastly different.

Let's start with just four main state-
ments: one to give us a starting point for
our plot of a bouncing ball, one to clear
the screen, one to plot the ball, and one
to repeat the plot.

JR-200 TSIOOO:

10X=2:Y=2 10LETX=2

50 CLS 15LETY=2

160 PLOT X,Y 50 CLS

190 GOTO 160 160 PLOT X,Y
190 GOTO 160

This is definitely a long way from
bouncing, so let's get the ball moving by
adding the following lines. Remember,
use SLOW mode on the TSIOOO if you
want to see the ball.

JR-200 TSIOOO

20 1=1 : J=1 20 LET 1 = 1

90X=X+I 25LETJ=1

100Y=Y+J 90LETX=X+I

190 GOTO 90 100LETY=Y+J

190 GOTO 90

As you can see, the same thing hap-
pened as with the border program,
namely, the values exceeded the dimen-
sions of the screen. To avoid this, we
must add four IF statements to test for
the screen edges. On the TSIOOO version,
we combined them into two statements
to increase the speed a little. (As you
know, SLOW mode really is SLOW!)

JR-200:

110 IF X>=62 THEN l=-l

120 IF X<=1 THEN l=-l

130 IF Y>=46 THEN J=-J

140 IF Y<=1 THEN J = -J

TS1000*

110 I F*X>=62 OR X<=1 THEN

LET I =- I

130 IF Y>=42 0R Y<=1 THEN

LET J =-J

What happens when you RUN the
program now? Try it and see. Just for
kicks, on the JR-200 version add line
150 to change the color of the ball:

150 COLOR ( INT( 1+6«RND(0)) )

While these programs produce in-
teresting patterns, it is hardly a bouncing
ball because the computer does not erase
the previous ball position when it draws
a new one. Add these lines to do that:

JR-200:
7 COLOR 5
80 PLOT X,Y

190 GOTO 70

TSIOOO
80 UNPLOT X.Y

190 GOTO 70

Now the program works at it ought
to, but you may wish to add a few more
lines that give you the opportunity to
choose whether the trail of the ball be
erased or not. We also added a beep
when the ball hits the edge of the screen
on the JR-200. Here is the final
program:
JR-200:
10 X=2:Y=2
20 1=1 : J=1

30 PRINT ' 'Leave trail
(y.n)' '
40 INPUT A$

September/October 1983 ® SYNC

TIMEX

inczlair- in an

• Powerful - fully programmable 2K memory • Portable
- 6%" x 6%" x 1%" - 12 oz. • Expandable - Optional 16K
RAM module • Single-key entry commands

• Educational • Unique syntax-check report codes for
error identity • Accurate to 9v 2 decimal places for full
range math and scientific functions • Graph drawing
and animated display • Advanced 4-chip design
combining power, portability and affordable price.
TS1000 INCLUDES: Computer, power adapter,
leads/ plugs for connection to TV & cassette recorder,
TV/computer switch, full instructions, and computing
course manual.

TS1000 $54.95

ACCESSORIES FOR

TIMEX

inclair-11000 and ZX81

TS1 01 6 - Expands TS1 000 from 2 K to 1 6 K ol memory. (5 oz.) . $49.95

TS2040- 32Column thermal printer for TS1000 and ZX81 . . . .$99.95

Keyboard Mask for Your
ZX81/1000* Computer

FEATURES:

• Install in seconds. Remove
adhesive backing irom mask
and place over keyboard.

• All characters and symbols
reproduced on mask.

• Durable — formed with poly-
carbonate sheet-satin finish.

JE681 KEYBOARD MASK

The JE681 Keyboard Mask provides users of the
ZX81/1000 series computer the individual feel of
each keypad on the keyboard. The mask has a rais-
ed outline around each keypad allowing the user to
feel and correctly position their fingers onto the
keyboard.

JE681 KEYBOARD MASK $9.95 each

ZX81/1000* Keyboard
Conversion Kit

JE682AK KEYBOARD
KIT MOUNTED IN DTE-
AK ENCLOSURE. LIGHT
TAN PANELS WITH
MOLDED DARK BROWN
END PIECES. SIZE:
14V«"Wx3'/ l "Dx3V l "H

The JE682 Kit provides users of the ZX81 / 1000 series computers a full-size in-
dustrial keyboard hookup to their computer. The JE682 Kit allows the use of
either the full-size keyboard or the Sinclair/Timex Keyboard. The Kit also per-
mits the simple disconnection of the Sinclair/Timex Keyboard for portable
use. The JE682 Kit consists of a full-size industrial grade keyboard with 62
keys, 2 p.c. boards, 18" ribbon cable, DIP socket and 4 rubber feet. The
keyboard conversion kit can easily be mounted into the DTE-AK enclosure.
This enclosure is large enough to contain the ZX81/1000 computer and the
full-size keyboard together. A handy label representing the ZX81/1000
keyboard layout is placed on the enclosure

JE682-AK Keyboard Conversion Kit $99.95 ea.

(WITH DTE-AK CASE - AS PICTURED)

JE682 Keyboard Conversion Kit $59.95 ea.

(WITHOUT DTE-AK CASE)

DTE-AK CASE ONLY $49.95 each

'ZX81/1000 is a trademark of Sinclair/Timex

TIMEX

iinclair- software ]

THE ORGANIZER

An information storage program Store the names, addresses
phone numbers, birthday and anniversary dates ot your tr tends
and business acquaintances

Part No. 032000 $16.95

THE HOME ASSET MANAGER

A homP ini/entnry 'irryjrjm (hit -v. ■ ,. ; ^355 gj

fire or theft Records date of purchase, place of purchase,
description, price, senai number and model number
PartNo.032009 $12.95

VU-CALC

This program constructs, generates, and calculates large tables

for financial analysts, budget sheets, and projections An
immensely powerful analysis chart

Part No. 031000 $19.95

CHECKBOOK MANAGER

A personal or business checking accouni program to store and
sort banking transactions On 90-mmute tape, up lo 3.600 tran-
sactions can be stored

Part No. 032003 $15.95

ALL TIMEX SINCLAIR SOFTWARE AND TIMEWORKS SOFTWARE REQUIRE 16K OF MEMORY

TIMEWORKS SOFTWARE

WALL STREET

A game of competitive financial speculation Limited dollars to invest which will put you on Easy
Street or into the Poor House A financial advisor is available to assist you. but he is not always
right. 1 to 4 players
Part No. TM-1 $16.95

STAR BATTLE ~~

Realistic deep space adventure to save Earth You. the Captain of the Starship Columbia, attempt
lo save Earth from the Scions Realistic action and thinking game

Part No. TM-2 $16.95

$10.00 Minimum Order — U.S. Funds Only
California Residents Add 6'/i% Sales Tax
Shipping — Add 5% plus $1.50 Insurance
S^nd S.A.S.E. tor Monthly Safes Ftyr!

Spec Sheets — 30c each
Send $1.00 Postage for your
FREE 1983JAMECO CATALOG
Prices Subject to Change

VISA*

ameco

1355 SHOREWAY ROAD, BELMONT, CA 94002
Phone Orders Welcome (41 S) S92 8097 Telex: 176043

THE FLIGHT SIMULATOR

Take control ot highly maneuverable light aircraft. With controls,
instrumentation and navigational aids to avoid hazards in
landing

Part No. 033002 $19.95

SUPERMAZE

Navigate your way through a three-dimensional maze with trap-
doors, gold bars, marker stones, and compass Ten separate
mazes Three-dimensional graphs
Part No. 034006 $14.95

FROGGER

Plays like the arcade game Hop the frog over traffic, snakes
crocodiles and treacherous diving turtles before time runs out
Part No. 034012 $17.95

SUPER MATH

Dnii yourself on addition subtraction multiplication, and divi-
sion with five levels ol difficulty Each problem graphically
depicted
PartNo.033000 $14.95 ,

CIRCLE 39 ON READER SERVICE CARD

50 COLOR ,

60 CLS

70 COLOR 0,0

80 PLOT X,Y

90 X=X+I
100 Y=Y+J

1 1 I F X>=62 THEN I =- I : BEEP 1
120 IF X<=1 THEN l=- I : BEEP 1
130 IF Y>=46 THEN J = -J : BEEP 1
1 40 I F Y<=1 THEN J = - J : BEEP 1
150 COLOR ( INT( 1+6«RND(0) ) )
160 PLOT X,Y
170 BEEP

180 IF A$=' ' Y' ' OR A$=' ' y ' '
THEN 90

190 GOTO 70

TS1000:

10 LET X=2
15 LET Y=2
20 LET 1 = 1
25 LET J=1

30 PRINT ' 'LEAVE TRAIL?
(Y,N)' '
40 INPUT A$
50 CLS

70 UNPLOT X,Y
90 LET X=X+I
100 LET Y=Y+J

1 10 IF X>=62 OR X<=1 THEN l=- I
130 IF Y>=42 OR Y<= 1 THEN J=-J
160 PLOT X,Y

180 IF A$=' 'Y' ' THEN GOTO 90
190 GOTO 70

When a trail is left, the plot eventually
fills in only every other screen location.
How could we modify it to fill in every
location? There are two or three ways to
accomplish this, some of which produce
more interesting effects than others.
Hint: try doing it with a random variable
or tricky rebounds.
Vic-20:

The Vic program for making a bounc-
ing ball is altogether different from the
TS1000 and JR-200 versions because we
had to use POKE to produce the same
effect. Let's start with a few statements
to get a ball onto the screen and to make
sure that it can be seen against the back-
ground. The control character in line 30
is the clear screen control character.
30 PRINT ' '#' '
40 X=7680
60 CM=38400
80 B=2
1 10 POKE X,8 1 :POKE CM , B
That is, of course, a very long way
from bouncing, so we can get the ball
moving with the following lines. As in
the border program, we must add the
checking lines before you test the pro-
gram, unless you enjoy subjecting your
program to a possible crash. Also, be
very certain that you type in the check-
ing lines accurately; they are extremely
important. When you are writing your
own programs using POKE, you will
find that the computer can and will
crash. Then you will have to retype your
program, if you did not SAVE it first.
For experience, try changing the ad-
dresses of some of the POKE commands
and see what happens. It is not a pretty
sight.

50 I =23
90 CM=CM+I
100 X=X+I

120 IF X>8163 THEN l = l

-44

130 IF X<7702 THEN l = l

+44

140 IF (X-7680)/22=INT

( (X-7680)/22) THEN l=l

+ 2

150 IF (X-7679)/22=INT

( (X-7679)/22) THEN l=l

-2

190 GOTO 80

Now you can modify line 80 to what
is below. This new line 80 gives the ball
a random color. If the color chosen is
white (the starting background of the
Vic), a new color will be chosen. This is
accomplished by the IF statement at the
end:

80 B=INT (7*RND(0) ) : IF

8=1 THEN 80

Although this program produces
pretty patterns, it is still not a true
bouncing ball because the trail is not
erased. Line 180 erases the trail by
POKEing a space into the last position
of the ball.

180 POKE X.32

Now the program is complete, but
you may want more frills. The following
program, in addition to bouncing a ball,

gives you the option of erasing the trail
or leaving it, and it adds a beep when the
ball hits a side. Make sure you type this
in exactly as shown.

5 POKE 36874, 249

10 PRINT ' 'LEAVE TRAIL
(Y,N)' '

20 INPUT A$

30 PRINT ' '#' '

40 X=7680

50 I =23

60 CM=38400

70 A=36878

80 B=INT(7*RND(0) ) : IF
B=1 THEN 80

90 CM=CM+I
100 X=X+I

1 10 POKE X,8 1 :POKE CM,
B

120 IF X>8163 THEN l = l
-44:POKE A, 15
130 IF X<7702 THEN l = l
+44 :POKE A, 15
140 IF (X-7680)/22=INT
( (X-7680)/22) THEN l=l
+ 2: POKE A, 15
150 IF (X-7679)/22=INT
( (X-7679)/22) THEN l=l
-2:POKE A, 15
160 POKE A,0
170 IF A$=' 'Y' ' THEN 80
180 POKE X,32
190 GOTO 80

The Panasonic JR-200 Personal Computer

David H. Ahl

The Panasonic JR-200 personal com-
puter from Matsushita has been several
years in the making, and it was worth
the wait.

Handsome Styling

Outwardly, the JR-200 has modern,
pleasing styling. The plastic case mea-
sures 13.5" X 8.0" and slants from a
height of 1" in the front to 2" in the rear.
Finished in silver and matte black in the
keyboard area, the case is rugged and
durable.

Connectors and Switches

An 8-pin D.I.N, connector provides
for an NTSC composite video or RGB
monitor, while an RCA jack gives an RF
signal on channel 3 or 4 at a 75-ohm
impendence. On most current TV sets
with a 75-ohm F-type input the JR-200
produces a crisp, clear image, almost of
monitor quality.

Another RCA jack provides 8-ohm
audio output to an external speaker. Au-
dio power is more than adequate; people
in the rear of a 100-seat conference room
had no trouble hearing the internal
speaker during a demonstration.

A second 8-pin D.I.N, connector is
for the tape recorder. A DIP switch se-
lects either 600 or 2400 bps. We were
pleased to find that the JR-200 per-
formed reliably at 2400 BPS on modest
quality ($19-$29) recorders over a
reasonable range of volume settings on
standard tape.

Two other connectors are for a printer
and an external bus. Via this bus, the
JR-200 has a serial RS-232C port which
may be set up for half or full duplex, 7-
or 8-bit words, and odd, even, or no par-
ity. JR-Basic does not use the standard
format for RS-232C communications.
Although data may be transmitted by
using the OPEN-INPUT#/PRINT#-
CLOSE statements a routine is needed
to send or receive data on the end of the
line.

User-Friendly Keyboard

The keyboard has 63 "Chiclet" style
rubberized keys in standard typewriter
layout, a 5" spacebar, two double-width
shift keys, and a double-height return
key. The keys are V 2 " square with stan-
dard keyboard spacing.

As on the TS1000, each key can make
multiple inputs. The JR-200 has 253
built-in characters: 96 English letters,
numbers, and symbols; 5 Greek letters;
63 graphics characters; 79 Katakana
(Japanese) symbols; and 10 music and
other symbols. All told, this is an excep-
tionally rich character set, right down to
the inclusion of a happy face and stick
figure man. All the symbols are formed
within an 8 X 8 matrix as on the
TS1000.

Although the keys do not provide any
tactile feedback, each keystroke is
accompanied by a beep. All keys can re-
peat except CONTROL, SHIFT, RE-
TURN, and BREAK.

September/October 1 983 » SYNC

CHANGE YOUR

TIMEX/SINCLAIR lOOO DISPLAY

"TO FULL COLOUR" GRAPHICS

eolor'works

LOOK AT THE FEATUR

♦ Plugs into ZX81/1000 (edge connector)

♦ Latest technology with TMS99 18 V DP

(32 sprite levels)

♦ Module contains it's own memory

♦ All text will run on the color tv

S ! ! !

♦ User defined characters & graphics up to

256x192 pixels

♦ Module contains extension of basic

commands including: PAPER/INK/
BORDER/BIN/SPRITE/OUT/INP/etc.

KOLORWORKS COMES WITH A LIMITED WARRANTY ON PARTS AND WORKMANSHIP
USE YOUR KOLORWORKS IMMEDIATEL Y WITH A GAME CASSETTE FOR $9.95

This delightful game is designed for hours of fun using some of the color graphic capabilities of
KOLORWORKS. The cassette also contains a short program to familiarize you with some of the
commands and graphics.

n-nnmnrn mn m-irm ni m il i m 11 1 1 i nmnm i i i » i m 1 1 h rrn nrxinrnr-rrinnnnmn

Enjoy Game Fun With

MAMWORES

THE SOON TO BE RELEASED GAME MODULE
(prototype stage) WILL OFFER SOUND, ROM
CARTRIDGES AND JOY STICK PORTS FOR
YOUR TS10007ZX81.

♦ THE SOUND will be of arcade game quality
which you can program for music, animals, trans-
portation (auto, train, airplane, etc.) and ma-
chine sounds.

♦ ROM CARTRIDGES will have up to 8K of ROM
using either 2716, 2732 or 2764 EPROMS. We
will have pre-programed cartridges and blank
cartridges which you can program. We will be
offering a service to burn EPROMS from your
cassettes.

♦ JOY STICK PORTS will allow for the use of two "Atari"®compatible joy sticks.

SORRY PRICE IS NOT AVAILABLE AT THIS TIME! GAAMWORKS WILL BE AVAILABLE BY MAIL ORDER

FOR FURTHER INFORMATION, SEND $2.00 (Credited to Order).
At this time KOLORWORKS and GAAMWORKS is available only by mail order.

MAIL TO:

BRAINCHILD COMPUTER WORKS, INC.
P.O. Box 506
Pewaukee, Wl 53072

PRiCC

QTY

AMOUNT

KOLORWORKS

$149.95

CASSETTE

9.95

Shipping & Handling

4.95

Wi. residents add sales tax

is enclosed

TAX

TOTAL

ENCLOSED

My Dcheck d money order

Name

Street

City

State

Zip

Please allow six to eight weeks for processing. Thank you.
CIRCLE 7 ON READER SERVICE CARD

Screen Display

Like the TS1000, the screen display is
32 X 24, and PLOT gives medium
resolution of 64 X 48. However, very
high resolution images, up to 256 X
192, are possible with LOCATE (x,y)
which can address each of the 768
locations.

PLOT is also used with COLOR to
select character color, background color,
and display mode. Four display modes
are available: normal, user-defined
characters, inverse color of previous
characters, and alter background color
for positions following the cursor. When
we got the hang of it, we found the
COLOR command very powerful for
producing interesting, and occasionally
bizarre, effects.

Eight colors are available for fore-
ground and background use: blue, red,
magenta, green, cyan, yellow, white, and
black.

Sound

While the JR-200 is theoretically ca-
pable of producing tones from to
65535 Hz, realistically, the usable sound
range is about five octaves, an impressive
achievement in a computer of this size.
The simplest way of producing sound is
with BEEP 1 which turns on the beeper
(880 Hz or A above the middle octave).

The next step up is SOUND (P,L) in
which P is the pitch in Hertz (0 to
65535) and L is the length of the tone in
milliseconds (0 to 255). This is very easy
to use in a program.

More complicated are the PLAY and
TEMPO commands which permit play-
ing tunes with up to three parts over a 5-
octave range at any imaginable tempo.
Notes are stored in memory and may be
played either in foreground (pauses pro-
gram) or background (program contin-
ues) mode.

JR-200 Basic

JR-Basic is not Microsoft Basic, but it
is not far away either. Most of the com-
mands, statements, and functions are
identical or very similar. Let's look at
some of the more interesting and novel
features.

JR-Basic has immediate mode and
will execute most Basic commands di-
rectly from the keyboard singly or in
groups (separated with a colon) as long
as the maximum line length of 80
characters is not exceeded.

When the JR-200 is fired up, a copy-
right notice appears along with the num-
ber of free bytes. In all configurations,
2052 bytes are reserved for the Basic
work area and the remaining RAM is
available to the user. User memory can
be expanded to 40K. Basic occupies 16K
of ROM while video RAM, I/O, and the
built-in character set use another 6K plus.

JR-Basic requires that Basic keywords
be separated by at least one space or a
colon or semi-colon from other charac-
ters. This enhances the readability of fin-
ished programs.

Numeric values can range from 2.9" 39
to 1.06 38 and are stored and displayed
with nine digits of accuracy. Both nu-
meric and string variable arrays can
have one or two dimensions. Unfortu-
nately, variable names are restricted to
two letters or a letter and a number.

All the standard operators are avail-
able: arithmetic, relational, logical and
string concatenation. LET is optional.

RUN performs its usual function but
can also be imbedded within a program
to run another program or to run the
existing program from any specified line
number, e.g., RUN 480. When used with
a filename (RUN "Border"), it will load
the program from tape and then run it.

The functions HOPS and VPOS re-
turn the current horizontal and vertical
position of the cursor respectively.
PEEK and POKE function as on the
TS1000. An unusual function is
VARPTR which returns the memory
location where a particular variable is
stored.

On-Screen Editing

A delightful feature of the JR-200 is
full on-screen editing. To correct a mis-
take or make a change you simply list
the line or group of lines to be changed,
and move the cursor with the four direc-
tional keys to the character to be
changed. Then type in the change or use
the insert, delete, or rub out keys. You
then move the cursor to the end of the
line and type RETURN. Whoosh; the
change is made.

FIND searches for a string of charac-
ters and then lists the line(s) with that
combination of characters. LFIND per-
forms the same function but lists the
lines on the printer.

Tape Handling and Files

LOADing and SAVEing are done as
on the TS1000, but there are some addi-
tional commands.

MSAVE and MLOAD permit files or
other material to be saved and loaded di-
rectly from and to memory.

MERGE enables loading one program
at the end of another.

VERIFY checks to see if a program in
memory and on tape match.

PRINT # stores files of data (not
programs) sequentially on tape, and IN-
PUT # reads back the data. While
sequential tape files are not nearly as
handy as random access disk files, the
2400 bps I/O speed is quite tolerable.

Printed Output

The JR-200 has five printer com-

mands: LPRINT and LLIST as on the
TS1000; HCOPY which is the same as
COPY on the TS1000; TAB which tabs
over from the left margin; and SPC
which spaces over from the last cursor
position.

Joysticks

Two DB-9 sockets accept standard
Atari-tyupe joysticks. Values form them
can be read into programs by means of
the STICK function.

Monitor Commands

The JR-200 allows machine language
aficionados to get into the monitor and
the assembly language.

The monitor has only three com-
mands: D, M, and G. D displays 128
bytes of memory from the location from
the address specified and allows you to
alter them. G begins execution of an
assembly language program from a
specified address. Memory locations are
all in hexadecimal.

Software and Support

Panasonic is sincere in trying to pro-
vide support for the JR-200. All the
early machines have been put in the
hands of software developers such as
Datamost — a smart move for getting
third party software on the market. Also
Datamost has produced a version of
their book, Kids and the Apple, for the
JR-200. Likewise, we are in the process
of producing a volume in our ideabook
series for the JR-200, The Panasonic JR-
200 Ideabook.

On the other hand, the preliminary
JR-Basic manual is tough going, has
very few programming examples, and
could in no way be considered user-
friendly. We are told that the Datamost
book will be supplied with the JR-200 as
the Basic programming primer.

In Summary

The Panasonic JR-200 is one of the
nicest new computers to make the scene
in some time. Attractively styled and
easy to use, it boasts an excellent, if not
standard, Basic language. The graphics
are very approachable and, although
resolution is not exceptionally high, the
character set is excellent and allows the
creation of detailed images. The key-
board is among the best of its type and
the separate cursor movement keys
make on-screen editing a joy. The JR-
200 is cassette tape oriented and uses it
well for program and data storage.

Peripherals, documentation, software
and support are, at this time, question
marks although Panasonic appears to be
moving in the right direction on all
fronts.

At the suggested list price of $350, the
JR-200 is an excellent choice. S

September/October 1 983 « SYNC

Its

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letter From englend

Stephen Adams

Dear Readers,

The number of computer shops selling
small micros is growing daily as is the
number of different computers available.
But one advantage none of them except
the ZX computers seems to have is
SYNTAX checking (that annoying rou-
tine that tells you that you have made a
mistake and that the computer will not
accept the line) on entry. Also most of
them have made economies along the
way, so that user-friendliness goes out the
window, so I still think you have to go a
long way to beat a Sinclair!

By the way, did you know that a com-
puter magazine which does comparisons
between various computers month by
month for the business man compared
the ZX81 with the brand new, very expen-
sive IBM Personal computer and found
that on some arithmetic examples the IK
machine was faster than the 16 bit 128K

IBM machine! and on another 16 bit 128K
RAM machine only 1.6K was left for the
user to program with after the machine
had taken up its demands on the RAM
for running the computer. This is about
the same as the TS 1000!

Software Developments

Software Libraries

A lot of argument has developed re-
cently in England about a new set of
companies called software libraries. They
lend you tapes (after you have paid a
small membership fee) of your favorite
software for a period of a week or two to
see if you want to buy it. If you do, then
you get a discount on the purchase price
of the tape. If, however, you want to try
another tape, then you pay a small fee,
varying from £0.50 to £1.50 to exchange
the tape.

Software companies are, of course, not
in favor of this system as it stops direct
sales of tapes to the user. This is because
the libraries can use the same tape over
and over again. The libraries say that
they ban copying by any of their mem-
bers. However, it is becoming so easy to
copy ZX81 and Spectrum tapes that they
cannot guarantee it.

Some software companies have refused
to deal with these libraries and have even
started court proceedings over the matter.
They say the hiring of tapes is prohibited
by the copyright law and that the libraries
are breaking it by encouraging copying
of their tapes by making it so cheap. Since
the cost of a blank tape is only £0.50,
copying a tape costing over £3.50 for a
friend becomes tempting and profitable.
The question of whether copyright applies
to computer program tapes has never
been settled in court.

This, of course, worries not only the

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CIRCLE 51 ON READER SERVICE CARD

Assemblers convert machine code written in mnemonics
to the numbers the CPU will accept.

ZX software producers but also com-
panies like Commodore (Vie-20/64 and
Pet) and Atari .

However, the buy 'n' try scheme re-
duced its buy back period to one month
which suited the software companies and
(he case never went to court. It would
have been nice to see a precedent set as
regards software piracy and copying. Both
sides would have something to go on.
The Law has a very grey area here.

Compilers and Assemblers

Another new market is the increase in
software utilities such as Basic compilers
for the Spectrum* These allow ycu to
convert a very SLOW Basic program into
a super fast machine code version. How-
ever, they do suffer from two problems:
1) the compilers cannot handle strings
and floating point numbers (only in-
tegers), and 2) the final code contains
what is called "RUN TIME routines" with-
out which the code will not work. These
"Run Time Routines" are copyright, the
compiler writers claim; and, since they
must be included in every machine code
written by a compiler, they claim you

must ask their permission land pay them
a fee) before selling that program. This
sounds a bit daft as the compilers them-
selves use Sinelair\s ROM routines (which
are copyright I. but they don't pay Sinclair
a penny!

Another useful utility is an assembler.
This converts a machine code written in
mnemonics (a bit like Basic) into the
numbers the microprocessor will accept.
It also allows you to use variables called
LABELs which specify a routine or area
of memory to be sorted out later.

A very good assembler for the
Spectrum is called ZEUS from Crystal

just like Basic. It also has a full screen
editor which allows you to use the cursor
keys to delete or add text in any part of
the screen. The text (or source file as it is
known) can be printed on to the Sinclair
printer or SAVEd and LOADed separ-
ately from the assembler. The assembler
also allows you to locate the code any-
where in memory or to assemble it for
running somewhere else (in case the area
you want is being used by the assembler).
A monitor is also included which allows

you to view and alter memory with the
same full screen editing. It also includes a
hex to decimal and decimal to hex calcu-
lator. It makes writing machine code as
easy as Basic as it reports any errors found
in assembly or elsewhere. A disassembler
is also available from Crystal to com-
plement the assembler.

Imagine Software

Imagine Software has surprised the
news here by paying programmer £35,000
a year to write games for them. Imagine
is a breakaway group from Bugbyte who
decided to go independent and is now

into a iiiui.i-i.iiii.uii pound iumovci uusi-
ness. Their fame is based on the fact that
all of their games are new ideas, not
rehashes of arcade games. Arcadia,
Schzoids, and Wackey Waiters are some
of the best selling machine code games
around and must be the craziest! Wacky-
Waiters, for instance, requires you to
deliver food to the guests in the diner,
dodging the boss and drunks, and not
spilling the drinks on the way. Imagine
also promotes the designers of the games
by naming them on the software pack-

UNDERSTANDING THE MANUAL?

No problem. Understanding Sinclair Basic
is a newly developed learning aid which
displays and demonstrates 34 Sinclair
Basic commands. Basic program lines are
displayed and simultaneously run on a
split screen. Go as fast or slow as you like
because the program waits at each line
for your cue to continue. Repeat each
program as often as you like by pressing a
key. Written in machine language and
basic, Understanding Sinclair Basic gives
you a powerful tool with which you can
unlock the mysteries of Basic program-
ming. 16K required.

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NEW YORK STATE RESIDENTS ADD 8% SALES TAX.
SEND CHECK OR MONEY ORDER TO A. + ASSOCIATES,
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CIRCLE 82 ON READER SERVICE CARD

SINCLAIR

ZX81/TS1000

NYLON

FORM FITTING

DUST COVER

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Protect your ZX81 from dust, grime and spills with a
quality dust cover from The Computer Trader. The form
fitted cover provides protection during storage or
transport. Available colors: black, tan. royal blue,
brown, navy blue and burgundy.

DEALER & DISTRIBUTOR INQUIRIES WELCOME
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(619)283-9273

CIRCLE 18 ON READER SERVICE CARD

Joysticks must now be programmable or have a
conversion tape to fit the popular games.

aging. And what is so special about their
programmer? He has only just left school
and at 16 cannot apply for a credit card
or a bank account to put his money in! A
wide variety of software is now appearing
for the Spectrum from astrology to music
composition. The music composition pro-
gram, for instance, allows you to write
the tune on the stave (music bars) which
appears on the screen in note form using
very good graphics. Tunes can be stored
and played back either as BEEPs or using
an external 8910 sound chip which gives
three notes, envelope, and noise. This
program should run quite effectively on
the TS2000 as it should have one of these
chips built in.

Weekly Computer Magazines

At least one of the weekly (yes, I do
mean weekly!) hobby microcomputing
magazines has taken a stand. They will
not accept any advertising from software
libraries that do not have an agreement
with software houses whose tapes they
are using.

The number of weekly magazines for
hobby computing has recently increased

to three with the advent of Home Com-
puting Weekly (from the Publishers of
Computing Today) and Personal Com-
puter News (from the publishers of Per-
sonal Computing World). Popular Com-
puting Weekly had been launched in April
1982 by Sunshine Publications. Micros
and their products are now moving so
fast that it only takes a week for the
whole situation to change. These are not
trade papers as they contain reader let-
ters, programs, and advice, all for £0.35 a
week!

Hardware
Developments

Joysticks

The main features of the hardware side
seem to be that joysticks must now be
programmable or have a conversion tape
available to fit them into the most popular
games. Some of the major companies
have even been persuaded to write into
their games a piece of software to use
joysticks made by Kempston Microelec-
tronics. AGF is one of the companies
whose joystick has now been made pro-

grammable It takes an ordinary Atari type
joystick and converts it to operate the
same as pressing any key, so there is no
conversion required in software for any
new game.

Printer Interfaces

Printer interfaces for the Spectrum
have also been making their presence felt
in large numbers to complement some of
the commerial software available.
TASWORD, a very fast 61 character per
line, stores its text on tape (Sinclair's
microdrives still have not made an ap-
pearance). Originally it could print out
only on the Sinclair printer, but Hilderbay
and others have now produced an inter-
face box with a Centronics cable which
will operate through TASWORD and its
own driver software to print out on a full-
sized printer. The graphics characters can
be reprogrammed to give control char-
acters such as underline, proportional
text, enlarged and double height char-
acters under user control. Also 132 or 80
characters per line make a great dif-
ference in formatting a page of text so
that it looks a professional job.

CLICK!

with the

KRADLE

$195 INTRODUCTORY PRICE

Full-sized. 50-key keyboard, 64K bytes ol RAM and more in a compacl
metal case that holds your fully assembled ZX-81 /TS-1000

•CRADLE'S conventionally styled keyboard uses tactile "click" switches,
a full space bar. double width keys for shift and enter

Mine extra automatically shifted keys Function, Graphic, Edit, Delete,
List and Cursor Arrows

Improved compatibility memory design lets KRADLE use all 64K

Cassette enhancer makes recorder volume of less importance

Joystick connector accepts ATARI 2600-type joysticks, mimics the
Graphic & Arrow keys

Pilot light shows power on and reset circuitry prevents operation under
marginal conditions

Supports two options the KRADLE Communicator serial expansion
with real RS-232 capability and the KRADLE Manipulator parallel
expansion for digital I/O (adaptable to parallel printer port).

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shipping, additional $2 50 for COD Michigan residents add 4% sales
tax. Personal checks— allow 10 days to clear.

CIRCLE 40 ON READER SERVICE CARD

MXP: Stores and manipulates
complex formulas without pro-
gramming:
•Solves equations
•Function plotting - output to
printer

•Complete function set (trig,
log, exp.,..)
User definable module

($15.95)

Engineering, Physic, Math
Modules ($19.95 ea)

S(OV I: Software controlled video inverter to improve
displays. No hardware needed. Auto merges with your
program ($9.95)

MEMOSHA: Allows the Seikosha, Radio Shack,
Gorilla, Banana printers to list the entire graphic set
using the Memotech interface ($15.95)

SPEC'TREX: Creates true perspective drawings
from user defined data points; viewing angles may
be changed at will; data is entered only once and is
maintained by resident file manager ($15.95 1

FINANCIAL MANAGER 1000; A completely
integrated business-home budget, expense, checking
and financial management system. Maintains
monthly and year-to-date records of 35 user defined
categories ($15.95)

INNOVATION CAN BE

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CIRCLE 67 ON READER SERVICE CARD

Three Centronics printer interfaces
have been produced for the Spectrum.
Softest's interface is designed to work
with the four color Tandy (Radio Shack)
Pen Printer which can draw diagrams
under software control. The other two
are designed to allow you to use any
parallel printer to LPRINT, LLIST and
COPY from inside a Basic program. Both
use Sinclair's own Basic commands to
control the output to the printer, so no
USR calls are required.

EuroElectronics interface box contains
a ROM which changes LPRINT and
LLIST commands to print on the Cen-
tronics printer instead of the Sinclair's.
LLIST, however, lists until it overflows
on the printer which gives sloppy listings
unlike what appears on the TV screen. It
also cannot handle graphics or special
characters like the underline symbol. To
COPY the screen means LOADing a tape
which puts a machine code program
above RAMTOP and a modification to
the GP100 type printers to remove the
automatic carriage return facility. If this
is not done, you get a blank line between
each character line. The interface costs
£53.48 and is so simple to use that all the
instructions are written on the bottom of
the interface box.

The second interface, from Kempston
Electronics, requires a machine code pro-

gram of 650 bytes above RAMTOP. A
Basic program modifies the machine code
to suit your printer and your program.
Once this is done, the Basic program can
be dispensed with and only the machine
code LOADed when required. The Basic
program allows you to select what char-
acters will be printed instead of graphics,
what type of printer you have (different
printers require different codes for double
width etc.), and, best of all, printer line
length. You can specify a 32 column line
length so that it prints out 'he listing just
like on the TV screen. The use of a Basic
routine for COPY, however, is a bit disap-
pointing as it is so slow. This is the most
user-friendly interface I have found so
far, cost £49.

Modems

One of the electronics component com-
panies has introduced a modem and
RS232 interface for the ZX81 (and soon
the Spectrum) to work 300 baud over the
telephone line. The restrictions on mo-
dems over here are rather stricter than in
the USA and hence the delay. PRESTEL
is still one of the promised facilities avail-
able when we get the right modem.

Tape Copiers

Tape copiers seem to abound, and it
would seem there is no way that a pro-

gram on tape cannot be copied. Most of
them work on the fact that the Spectrum
allows you to copy any part of the mem-
ory to tape. So, if you can write a program
which will load any program as machine
code and then SAVE it again as an area
of machine code, you end up with an
exact copy, whatever the software com-
panies try to do.

The best copier I have seen is called
ZAP 2.0 which is produced by Scimitar
Software. Copying is, of course, illegal,
but sometimes it is necessary to make a
back-up copy of your software in case the
tape recorder screws the tape up.

Sinclair Developments

The Spectrum was launched in Europe
(very quietly) in April 1983 although some
people had been arranging to get some
directly imported through friends. Each
country though wants programs and
devices written in its own language and
so the importers must do the conversion
as most of the software houses do not
change their software from country to
country. As long as this keeps up, the
European user will be short of both soft-
ware and hardware that is not home
produced.

RAM upgrades for the Spectrum have
been dropping in price, some are now as

FOR TOTAL

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of Your Timex Sinclair

Learning
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by David A. Lien

Please send

copies of Learning Timex Sinclair BASIC at
$14.95 each (Calif, residents add 6%) plus $1.65 shipping and
handling per book within the U.S. Foreign orders, include $2 50
surface shipping and handling per book.

Total Enclosed

Name

Address

City/State/Zip
Check

Visa

MasterCard

Account #

Expiration Date

Signature

Please allow 4 to 6 weeks
for delivery. 070983

I
I
I
I
I
I
I
I
I
I
I

CIRCLE 14 ON READER SERVICE CARD

low as £20 for the Model 2 machines.
Sinclair has dropped the supply of RAM
boards to Model 1 users due to the fact
that he cannot compete with independent
companies prices (the Model 1 needs a
PCB instead of just the ICs as there are
no sockets for RAM chips).

Sinclair has also dropped the micro-
drive for the moment, but has promised
that the first 100,000 purchasers of the
Spectrum will be given the first chance to
buy them when they are available. He has
aiso dropped the modem that was going
to interface to the telephone line to pick
up PRESTEL, a nation wide database run
by Britain's telephone company.

This has disappointed the producers of
a special service called Micro-Net 800
who have had to look elsewhere for mo-
dems for the Sinclairs. Other machines
can already be connected up via an RS232
interface using an acoustic modem and
some specially written software. The idea
of Micro-Net was to sell or give away
software over the phone lines as well as
providing an information service simular
to the Source in the USA. The service
would cost approximately £100. This in-
cluded the price of the modem and soft-
ware to run it over the membership period
of a year. At least 100 free programs were
to be made available for each type of
microcomputer and at night access to the

Micro-Net would only be the cost of a
local phone call.

Sinclair has reduced prices over here
to £39.95 for the ZX81 and £99.95/
£129.95 for the 16K/48K models of the
Spectrum.

The companies I have mentioned are
all in England and are listed below.

Kempston Microelectronics Ltd., 180A
Bedford Rd., Kempston, Bedford MK42
8BL. Tele: 0234 852997.

AGF Hardware, 26 Van Gough Place.
Bognor Regis, W. Sussex P022 9BY.
Tele: 0243 823337.

TASWORD, TASMAN software, 17
Hartley Crescent, Leeds LS6 2LL.

Hilderbay Ltd., 8-10 Parkway, Regents
Park, London NW1. Tele: 01 485 1059.

Scimitar Software, 3 Palace Gates
Road, London N22 4BW. Tele: 01 889
1099

Crystal Computing. 2 Ashton Way, Sun-
derland SR3 3RX.

Home Computing Weekly, ASP, 145
Charring Cross Road, London WC2 EE.
Tele: 01-437-1002/7

Personal Computer News, Evelyn
House, 62 Oxford Street, London W1A
2HG. Tele: 01-439-4242

Popular Computing Weekly, Hobhouse
Court. 19 Whitcombe Street, London
WC2 7HF. Tele: 01-839-6835.

Softest, 10 Richmond Lane, Romsey,
Hants.

EuroElectronics, 29 Clarence Square,
Cheltenham, Gloucester. Tele: 0242-
582009.

Imagine Software, Masons Buildings,
Exchange Street East, Liverpool L2 3PN.

Glitehoidz
Report

Connecting a Monitor to the TS1000.

3:4.

The schematic should show a line
from Gnd to the shielded cable as in
the diagram below.

Gnd
\ Video

i^TT®

Shielded cable
to monitor

NPN '

transistor

ti-L| thi

"Try This" features short programs to show off your computer, impress your
family and friends, and tickle your imagination when SYNC arrives at your place.
Send your contributions to: Try This, SYNC, 39 E. Hanover Ave., Morris Plains,
NJ 07950.

8K ROM; IK RAM

Type in the following lines:

1 3L

3 ^s;-

* POf 5 1642

5 :

Press RUN and ENTER. Observe the
results. Can you figure this one out? Our
thanks to:

Michael Allen

48 Deerpath Rd.

Chalfont, PA 18914

8K ROM; any RAM

Type in the following lines:

20 _§^ R = INT RNE *5 +10

:o fop o=p tc =i

-i-0 PPIr;T ~- z ■ •

50 next :

60 print rt int rnd* 17-p i +p

70 FOP 0=5 TO R-l

30 PCTtiT RJ ■ I

SO NEXT *
100 NEXT •

Put the computer in SLOW mode for
best results. Press RUN and ENTER. Ob-
serve the results. After you have digested
the display, try the variation in the fol-
lowing lines:

20
30

'0
80

"I
100

FOP > =0 TC
^5^ R = INT

31
RNC ■

FOR 2-h TO 20

= ._o

PRINT
NEXT Z

FOP 0=5 TO R_i
print fly g . m
NEXT
PRINT h^ INT RND* R-

Press RUN and ENTER. Which vari-
ation do you prefer? Our thanks to:
Tuan Ton
6837 Carnegie Dr.
Richmond. VA 23226

8K ROM; IK RAM

Let's try Eric Chandler's "Try This"
again {SYNC 3:4):

20FORN=lTO5

30 PRINT CHR$(38+INT(RND*26+

.5));
40 NEXT N
50 PRINT "###";
60 GOTO 20

Press RUN and ENTER; press CONT
and ENTER for another screen. What
happens here?

Line notes:

20: 5 letters

30: A random letter A-Z

50: 3 spaces after each word (8 * 4 = 32
= a full line).
Our thanks for the correction to:

Eric Chandler

1523 Club Terr.

Lynchburg. VA 24503 H

September/October 1983 ® SYNC

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Features:

Any Two TIMEWORKS Programs Listed
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• Allows provision for one Print-
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$3405

Cat. No

1101 THE QUIZ KIT™ Educational
learning system. Construct
your own quizzes. 1 6K Req.

1201 5-2 GAMES'" Five challeng-
ing and entertaining games.
2KReq.

1202 STAR BATTLE™ Realistic
deep space adventure to
save Earth. 16K Req.

1203 ROBBERS OF THE LOST
TOMB™ Perilous adventure
in search of the Sacred Tab-
lets. 16KReq.

1 204 WALL STREET™ A competi-
tive game of financial spec-
ulation. 16KReq.

1205 PRESIDENTIAL CAMPAIGN™
Conduct a nationwide cam-
paign to become the next
President of the United
States. 16KReq

1207 SCYON'S REVENGE™ Real-
istic deep space combat ad-
venture. 16K Req.

1301 THE MONEY MANAGER™
Home and business budget
and cash flow system. 16K
Req.

Cat. No

1302 THE COLLECTOR'S COM-
PANION'" Cataloging and
inventory recording system
for all collectibles. 16K Req.

1303 THE INSURANCE PROPER-
TY RECORD™ Home con-
tents inventory recording
system. 16K Req.

1304 THE ELECTRONIC CHECK-
BOOK™ Check recording,
sorting and balancing sys-
tem. 16KReq.

1306 FORGET-ME-NOT™ A re-
cording and retrieval system
for important occasions,
events and appointments.
16KReq.

1307 DATA MASTER™ A general
information storage and re-
trieval system — with exclu-
sive "X-SEARCH"™ Fea-
ture. 16K Req.

1308 5-2K FAMILY PAK™ 5
Household programs for the
basic T/S 1000 and Sinclair
ZX-81 Computers. 2K Req.

1401 PROGRAMMING KIT 1™ A
practical "How-To" learning
approach to Basic program-
ming. 16K Req.

You save

COMPLETE MONEY BACK GUARANTEE

If, for any reason, you are not completely satisfied, you may
return The Computer Control Center, in good condition
(freight prepaid), for a full cash refund. (Software not
included).

RUSH This Coupon Today.

mbr

DISTRIBUTORS

P.O. Box 321. Deerfield, IL 60015 (312) 291-9284

MBR Distributors

PO Box 321 Deerfield, IL 60015

Rush me Computer Control Centers @ $29.95/ea

Plus postage & handling @ $4.70/ea

(Illinois residents add 6% sales tax)

ALSO INCLUDE TWO FREE PROGRAMS
(Additional Software @ $1 6.95 ea)

Cat. No. Qty.

@ no charge

@$16.95/ea

TOTAL

N/C

Name

Address .
City

. State .

Zip.

Check or MO □

Card No

Signature

VISA □ Master Charge D

American Express □
Exp. Date

Dept. SY-9

CIRCLE 71 ON READER SERVICE CARD

resnurr.

The "Resources" column lists new products for Timex/Sinclair users. Suppliers
and users are invited to send brief product descriptions and details for ordering to:
Resources, SYNC, 39 E. Hanover Ave., Morris Plains, NJ 07950.

Address Change

Biocal Software, Inc.
167 Wilson St.
Petaluma, CA 94952

(800) 237-8400. x70

Note: Biocal customers who
bought tapes prior to April 1983
which would not LOAD can return
the tape plus $1 for s&h for an
updated tape with documentation.

Services

Repair Service/Maintenance
Agreements

Renewable maintenance agree-
ment keeps your system running.
The only Sinclair Research Ltd.
authorized service center in the
nation. For further details, write
to:

MicroSync Services

Box 2015

162 Marlboro St.

Keene. NH 03431

Programming Aids

Program Name Reader

Reads all names of programs on
tape: prints to screen or to printer.
Sees names one at a time as they
are read from tape. Operates from
REMark statement at 16514. Add
$1 for customization to another
location. IK MC. Unusual bonus
program included. Listing: $1 plus
long SASE.

Multiple Programs in Memory. 2K
RAM.

Store from 2 to 47 programs
depending RAM. Allows programs
to be swapped in a split second.
Memory is divided into uniform
sections: so programs must be
roughly same size. Customized ver-
sion that resides in 8K to 16K

block: SI extra. MC. Listing: $1
plus long SASE.

John Richard Coffey

PO Box 448

Scottsburg, IN 47170

BEST Computer Coach

Audio instruction tapes and
computer program tape package.
Presents audio-visual show for
teaching the meaning and relation-
ship of commonly used computer
terms. For TS1000, but versions
available for other computers.
Write for information. $19.95.

Boston Electronic
Systems Training

1420 Providence Hwy.

Norwood. MA 02062

Engineering

Passive Solar Design Pack

Calculates heat loss, solar gain,
solar fraction, storage mass. $87.85.
SASE for list of programs.

Surveyors Travers Correction

Adjusts angles turned, bearings.
error of closure, area of plot, for
closed, loop travers. $52.85. SASE
for list of programs.

MCS Software

2816 Edmond St.

St. Joseph, MO 64501

Aircraft Performance Program

Charts climb rate vs airspeed to
make performance comparisons of
aircraft under varying conditions
of weight, power, and altitude.
Booklet with listing, explanation of
all equations, and a tabulation of
specifications for 250 production
and homebuilt aircraft: $7.95.

Robert Fingerle

PO Box 7793

Fremont, CA 94537-7793

Electronics/Radio

Electronics Engineer

Menu driven program for the
electronics hobbyist or engineer;
covers voltage division, LED volt-
age dropping, resistor color codes,
and Ohm's Law. CC and instruct-
ions: $4 pp. (money order).

Steve Dinstbier

1159W. TaftRd.

St. Johns, MI 48879

Litre ironies Subroutines. Combo II.
(FX1002)

Capacitive time constants; cur-
rent power dissipation inductance;
Ohms Law; Joules Law; parallel;
series resistance; parallel; series
capacitance; etc. $12.95; $1 s&h.

JPR Software

PO Box 4155

Winter Park, FL 32793

Morseman 3

Morse displayed as alpha num-
erics on screen. Training aid; pra-
ctice for speed and accuracy. Auto-
matic decode option for Morse
received by radio to be with suit-
able interface. Decode, generation
of preset messages, random gener-
ation for training. Speeds to 40
wpm. $20; $1.50 s&h.

D. R. Navigation

PO Box 151

Island Station

New York, NY 10044
(212)980-1646- 3084237

Navigation

Computer Navigation

7 programs: Great Circle Sailing.
Rhumb-line Sailing, Dead Reckon-
ing, Latitude by noon sight. Longi-
tude by Time Sight. Star and Planet
Identification, and Sight Re-

duction. CC and instructions:
$19.95 pp.

Celestial Software

3010 Warrington Ave.

Lakeland, FL 33803
(813)686-3311

Radiobeacon Qwikplot

Immediate indication of position
obtained from either 2 or 3 RDF
bearings. In the latter case, fixed
marker indicates median position;
flashing plot point shows the limits
of the "cocked-hat" indicating the
likely accuracy of the observations.
$10.

D. R. Navigation

PO Box 151, Island Station

New York, NY 10044
(212)980-1646, 308-4237

Math

Statistics Pack

Force, moment, couple, friction,
vectors, US-SI conversions. $19.74.
SASE for list of programs.

MCS Software

2816 Edmond St.

St. Joseph, MO 64501

Vectors and Hvperbolics
Functions. Combo III. (FX1004)

Hyperbolic functions; dot and
cross product of vectors; vector
addition and subtraction; etc.
$12.95; $1 s&h.

Mathematics of Higher Order.
Combo IV. (FX1006)

Arithmetic progression; area of
common figures; complex variables
and operations: exponents; deriva-
tives; logarithms; factorials; etc.
$12.95; $1 s&h.

JPR Software

PO Box 4155

Winter Park, FL 32793

September/October 1983 ® SYNC

SPEECH
SYNTHESIS

UNLIMITED
VOCABULARY

•Amplifier-t- Speaker

•Input for
Ears Music Units

SMART
EARS'.

NEtyi

SAVE$$
ONLY

Strip IC
Kit- S 29 95
Built
»69"

SPEECH
RECOGNITION

Vocal commands to a computet

MUSIC SYNTHESIS +16 Line control port (Kit
$49) (Built $59) FLOPPY DISC CONTROLLER
for 3 and 5.25 INCH Shugart compatible
drive (requires cable) for ZX-TS1000-Kit $79,
Built $99. Call for spec.

SUPER ROM BOARD has built in (1) Printer
Interface (2) Eprom Burner (Solid State mem-
ory) (3) Autostart ROM (Program run automat-
aclly everytime ZX is turned on, the best
thing for ZX) ONLY

ZX81

Floppy Disc
Controller

CIRCLE 5 ON READER SERVICE CARD

USER FRIENDLY SOFTWARE

for the T1MEX /SINCLAIR 1000

Data-Manager (DM)*

Screen prompted data collection sys-
tem with formula fields and both form
and spread sheet display
Finance-Manager (FM)*

Combines budgeting, record keeping,
and check reconcilement into one
operation
Program-Manager (PM)*

BASIC and machine code program
monitor and utility Functions include:
renumber, copy, delete, search, dump,
Hex load, Hex Debug, and a condense
mode that reduces program memory
size.

All programs are supplied on cassette with full
size instructions tnat are easy to read and easy
to understand. 16K required

$14.95 each postage included
VISA MASTERCARD or check

TOLL FREE ORDERS

1-800-543-3000 ask for

operator #520 item code*

COMPUTER ASSISTANCE INCORPORATED

PO BOX 3402 CINCINNATI OHIO 45201 / (513) 381-8778

CIRCLE 16 ON READER SERVICE CARD

3-Color Keyboard
Symbols with
Conversion
Instructions

Plastic symbols for converted TS1000/ZX81 keyboards;
color-coded on opaque background. Fit all standard-
size keys. Adhesive backing for easy application.

Easy, illustrated guide for converting a cheap (about
S20) surplus keyboard to a full-size TS1000/ZX8 1
console . "... as easy as stringing wire on a fence . "

Do's and Don'ts for selecting a surplus keyboard.

Diagrams and instructions for adding single-stroke
(automatic) SHIFTED function keys to your keyboard.

Bonus forthe "pro" - Schematic Diagram of Computer.

"Your keyto]

'Keytops' I order' have never

: now.

MULE Electronics *

AAA Lincoln Blvd. Dept . 310A y"0

Venice. California 90291

*Please add $1.50 P&H. California residents add 6.5%
tax. Money-back guarantee, of course .

SOFTWEAR

TRADEMARK OF EARTHSCENES

EITTrei si r-dear 1DD D IS A REGISTERED TRADEMARK
OF TIMEX COMPUTER CORPORATION

IDDD

II ' ttslncferj

1DDD
1DDD

1DDI

ran

TS103

Exclusive silkscreened designs on quality 50/50 cotton/poly Ts
Adult sizes: S.M.LXL; kids' sizes: S.M.L. $8.50 each, plus $1.50
shipping/handling. (Ohio residents, add 5.5% sales tax I
COLORS. TS101— BLACK AND BLUE design on It blue T only;
TS102 & TS103— BLACK on red. It. blue or yellow T WHITE on
black T. TO ORDER, specify quantity, size, color and design
EARTHSCENES • PO BOX 21487 »COLUMBUS. OH 43221

CIRCLE 28 ON READER SERVICE CARD

CIRCLE 45 ON READER SERVICE CARD

Super Fn Plot. 2K RAM.

Plots any function in the form
y=f(x); draws it to the correct ver-
tical scale on screen; plots are
white on black background. Com-
piles a MC routine to plot same
function at high speed. Compiled
MC is relocatable. Very simple text
editor included. Listing: $1 plus
long SASE.

John Richard Coffey

PO Box 448

Scottsburg, IN 47170

Graphics

Inverse Graphics Subroutines. 2K
RAM.

8 subroutine listings with loading
tips and full instructions. MC. List-
ing (including StarShip Trip list-
ing): $5 pp. SASE for list of avail-
able programs.

M. T. Ehasz

104 Davis St.

Philadelphia, PA 19127

Character Set Graphics Kit

Add large format letters and nu-
merals to your programs. Make
electronic posters. 6 page 8 1/2 x
1 1 illustrated pamphlet describes
how. Can be used for any com-

puter with graphics symbols. $2
plus SASE.

Vidiom

PO Box 3118

Providence, RI 02906

Programs
Business/Household

Checkbook

Balance your books. For more
information write:

E & S Software

PO Box 196

Budd Lake. NJ 07828

ZXPhonelist

Stores from 100-200 entries in-
cluding name, street address, city,
province or state, postal code, tele-
phone area code, telephone num-
ber; add, delete, sort entries; dis-
play on screen or print. Specify
French or English version. MC.
$14.95 Canadian.

Micro Da et Fils

PO Box 7221 RR2

Gatineau. Que.

Canada J8P 6H8

Ledger

Double entry journal and ledger;
single entry to both a credit and
debit account; date, check number,
amount, credit and debit accounts,

memo; define and classify your
accounts; self-expanding to RAM
over 16K. 100 transactions to 50
accounts in 16K; over 700 in 32K.
In Basic for user modification. $10
pp.

D. Lipinski Software

2737 Susquehanna Rd.

Roslyn, PA 19001

Business Subroutines Package.
Combo I. (FX1000)

Future value; time periods; pre-
sent value; interest rate. $12.95; $1
s&h.

JPR Software

PO Box 4155

Winter Park, FL 32793

SixPac

6 programs: FORTH interpre-
ter/compiler, spreadsheet, inven-
tory, calendar/reminder, house-
hold budget, data base manage-
ment. $25.95; $3 s&h.

SofTek

Box 4232

Santa Fe, NM 87502

Philatelist

Stamp collection file and invest-
ment analyzer. Stores Scott no.,
description, date purchased, from
whom, condition, cost, number of
copies. Calculate investment po-

tential and analyze performance.
Up to 200 stamps per program.
Used for other collectibles. $26.85.
SASE for list of programs.

MCS Software

2816 Edmond St.

St. Joseph, MO 64501

Fylit

User generated customized data-
base applications. Requires 64K,
CAI P40 printer, and CAI Exatron
Stringy Floppy drive. 5 program
overlays which share a common
data file. $30.

Biocal Software. Inc.

167 Wilson St.

Petaluma, CA 94952
(800) 237-8400, x70

Demonstration Tapes

TS Demo

TS1000 demonstration tape for
retailers to increase sales or for
anyone wanting to show off the
computer. ZX81 version available.
Specify. $10; $1 s&h.

K. Roberts

PO Box 2202

Davidson, NC 28036

Demonstration 1000

TS1000 retailers: demonstrate
the capabilities of the TS1000 with

R.I. ST Inc. ANNOUNCES

SPEECH

SYNTHESIZER

£ SALE &■

$59

"ACT NOW: Receive

Exclusive Phrase Finder Program 'S5. VALUE FREE"
Speech Synthesis Instruction Manual "$10. VALUE FREE'
ORDER NOW SALE ENDS 9/30/83

HEAR THE PO-V6R

.<V1

,0*'

jrt

MOW YOU CAN MAKE YOUR COMPUTER TALK

The PARROT newly introduced by R.I.S.T., gives the
Dower of speech to Timex Sinclair Computers. This simple
to use plug-m speech module is capable of generating all the
sounds in the English language The combination of these
sounds, in the order of your choice, will generate an
unlimited vocabulary of words, phrases, and sentences as
well as an array of sound effects Phggy-back

expandeb'liTy allows other modules (eg. memory) to be
operating with the Parrot simultaneously

ii Donnelly had this to say in the April issue of Syntax:

Documentation is professional.. "

Overall, R.I. ST s Parrot is an excellent unit and per-
cms up to and behond my expectations

SALE

Send To: B.I. ST Inc
Depl. 214 (Fomerly
Voicetecht

P Bo» 499 Ft
Hamilton Station

Brooklyn. N V
11209 12121259-4934

Please send me f

Parrotlsl Speech Syn.
thesizers for my Q
ZX80 D ZX81 D

TS10O0 at (59.95 ea plus
M OOsh/hd.

I will also receive an exclu-
sive phrase finder pro-
gram and a 40 page in-
struction manual. FREE
15 DAY MONEY BACK
GUARANTEE C O D
ORDERS ADD 11. Tl
PAY BY BANK CHECK
OR MONEY ORDER
NTS RESIDENTS
ADD 8'/.% TAX

CIRCLE 54 ON READER SERVICE CARD

ABERSOFT
7 MAESF ALLEN, BOW ST, DYFED, ENGLAND SY24 5BA

ZX81 & Spectrum
Games

Chess 1.4: Ten level m/c graphic screen display.
16K ZX81 $17.95

Invaders: Very fast m/c action. Includes mystery

ship and increasingly difficult screens.

16K ZX81 $8.95

Mazeman: A fast action m/c game that reproduces

the spirit of the original. The Spectrum version

includes excellent graphics.

16K ZX81 $8.95— Spectrum $9.95

Can also be used with AGF joystick.

Adventure 1: Based on the original game by
Crowther, this game was the start of the Adventure
craze. Reviewed Sinclair User, issue 2. Features
Save game routine as the game can literally take
months to complete.
16K ZX81 $17.95— 48K Spectrum $19.95

We have a full stock o( all programs and supply by return of

post (which is included in the price)

Add $2.00 for postage /handling

CIRCLE 81 ON READER SERVICE CARD

games and business displays in-
cluding machine language routines.
Self-running; load the cassette and
leave. $9.95; $1.50 s&h.
Michael B. Williams
1300 DePaul Way
Virginia Beach. VA 23464

Music/Sound
Programs

Virtuoso

Music synthesis program. 10 oc-
tave range, whole to 32nd and dot-
ted notes and rests. Self performs
songs at any tempo; SAVE for later
use. Hear through TV, amplifier,
AM radio, or record. Instructions
include coding from written music
for non-musicians. Length expand-
ed to 1 50 notes. SASE from buyers
of 96 note version gets free expan-
sion instructions. $6.95 pp. US &
Canada: $9.95 elsewhere.

W. D. Maples

Dept. C-l

688 Moore St.

Lakewood, CO 80215

Beep Routine. IK RAM.

Produces tones over wide range
of frequencies. Attach earphone
(not included) through tape recor-
der and get sound that can be
heard several feet away. USR fun-
ction and 2 to 4 POKEs specify
frequency and duration. Bonus line
drawing program included. Rou-
tine can be customized to location
other than 16514 for an extra SI.
MC. Listing: $1 plus long SASE.

John Richard Coffey

PO Box 448

Scottsburg, IN 47170

Theile Cabinets

Complete program for design-
ing/testing bass and subwoofer
speaker cabinets. Includes simpli-
fied measurement procedures and
2 unique alignments for very small
bass cabinets. CC: $8.95; $1.50
s&h.

Mallard Software

c/o Eric Levine

203 S. Sherwood St.

Ft. Collins, CO 80521

Miscellaneous
Games

Earthquake

You are trapped in your shack
during an earthquake.

Tunnels

You are the evil Mazor creating
mazes that none can escape. One
or two players. For more infor-
mation write:

E & S Software

PO Box 196

Budd Uke. NJ 07828

ZX Reflex

10 round game with maximum
score of 5000 points. High score is
said by program (1 counter per
difficulty levell. 10 levels of diffi-
culty Specify French or English
version. MC. $14.95 Canadian.

Micro Da et Fils

PO Box 7221 RR2

Gatineau. Que.

Canada J8P 6H8

Supermastermind 1000

New twist on a familiar chal-
lenging game.

Hangman 500

Computer draws on over 500
words.

Rubitz

Play the "cube" on your com-
puter.

CC: $6.95 pp. per program; all 3
for $17.95 pp.

Mind Games

PO Box 2129

Sheffield Lake, OH 44054

The Great Glider Race

Race around a 100 mile course.
Decide when and how high to
climb in various thermals for the
highest course speed. IK program
uses text; 16K uses simulated in-
strument panel graphics. Includes
a discussion of glider flight for the
uninitiated. Listings: IK: $4; 16K:
$6.

Wordpuzzler

Hides words in a random char-
acter matrix. Search for them on
screen or on printout. Put in your
own words or use those stored with
the program. CC: $7.95

Robert Finngerle

PO Box 7793

Fremont, CA 94537-7793

Domino (SQ-1 1 1 )

28 dominos; play against the
computer; each starts with 5. Ob-
ject is to make opponent go to
boneyard or pass. This earns
points. $9.95; $1 s&h.

Yahtzee iSQ-\0l)

1 to 4 players. Roll 5 dice; im-
prove roll by rolling any or all of
the dice. Object: to score each
improved hand on 13 line score
sheet. Game is over when all the
lines are used. $9.95; $1 s&h.

Antropuss (SO-123)

Antropuss is a man eater living
in a cave of 20 rooms each with 3
tunnels. You must move from
room to room avoiding the antro-
puss and other hazards. You win
by shooting the antropuss with one
of your 5 arrows. $9.95; $1 s&h.

JPR Software

PO Box 4155

Winter Park. FL 32793

September/October 1983 « SYNC

LET YOUR ZX81/TIMEX 1000
WORK FOR YOU!

PERSONAL AND BUSINESS PROGRAMS:

Are on cassette, are menu driven, run with or without a printer and save
on tape automatically

SALES FILE 16K or 64K:

Holds (150 16K) (600 64K) products w wholesale and retail prices. —
Shows separate wholesale and retail totals and amount ot profit in up
to (25/16K) (100 64K) different accounts — Records inventory automat-
ically or manually. — Totals sales tax — Cash register mode totals,
identifies, adds sales lax, and keeps records for your bookkeeping. —
Prints a list of products, accounts, inventory and sales slips with printer.
•"A must for any small business"' $19.95

CHECKING 16K or 64K:

Lists (25 16K) (100 64K) deposits showing amount and date entered.

— Lists (80 16K) (500 '64K) checks and displays check number, date
and payee. — Lists by account total of checks written. — Keeps running
total of checks written and balance left in account. — Adds interest and
subtracts service charges. — Search for a check by number, name,
date or amount Print a list of deposits, accounts, and checks with printer
'"Great for lax records. "" $9 95

INVENTORY 16K or 64K:

May be used for everything from keeping an accurate inventory for your
business to your personal record collection. — Holds up to (150 16K)
(750/64K) items wcomments for each. — Comments may be used for
serial numbers, dates, prices or location. — Lists all items, search for
single item, change o r delete any item. — Sort items in alphabetical or
numerical order. — Prints a list of items, quantities ana comments
'"Everyone should have an inventory of household items in case
of fire or theft.'" $9 95

MAILING LIST 16K or 64K:

Holds (10016K) (425 64K) names, addresses and telephone numbers.

— Search by name, city, zip code, or phone number. — Will sort by
name, city, or zip code in alphabetical or numerical order. — Lists all
names, changes or deletes — Prints list of names or names and
addresses or address labels if they are available for your printer.
*"A valuable tool for your home or business'" $9 95

APPOINTMENT CALENDAR 16K:

May be used for everything from reminding you of birthdays to business
appointments. — Just enter the date and list up to (8) appointments per
day for up to (31 ) days. — Lets you change or delete any appointment.

— Print a list of appointments for day or month. Save all appointments
on tape.

""Keep a permanent record of past appointments'" $9 .95

FINANCIAL RECORD KEEPER 16K:

User can define and use 20 files of income and/or expenses which may
be noted as ia» deductible for future reference if applicable. — Informa-
tion may be reviewed in various ways. — Includes ability to correct or
change information already entered without knowledge of computers or
programming At end of year you have a complete overview of cash
flow for the preceding year and a list of tax deductible expenses. —
Prints all information with a Timex or compatible printer $14.95

FINANCIAL RECORD KEEPER PLUS - 48K:

Does everything the above 16K version does, plus keeps up to 500
checking transactions and it automatically reconciles the checkbook with
the bank statement.
*"A complete finance package"' $19.95

GRADEBOOK 16K to 64K:

A sophisticated, friendly and flexible grade management program for
teachers of all levels. — Ranks students by weighted or unweighted
average — An example of the program's capacities with 16K: 50 stu-
dents may have up to 40 exams — GRADEBOOK is limited only by
memory size.
'"Written by an instructor at Purdue University'" $9.95

INVOICE CONTROL:

A program designed to keep track of and print invoices for the small
business. — Is self-adjusting to memory size. — Will hold (20/1 6K)
(120/64K) invoices of up to (5/16K) (10/64K) lines each. — Review or
change any invoice, list all invoices, list invoices with an open balance,
enter additional payments and review invoices written to a particular
account. Prints your company name and address on each in-
voice $14.95

Send for free catalog of personal, business & educational programs such
as "CASH REGISTER.' MULTIPLICATION TABLES. MATH QUIZ and
FLASH SPELLING at $9 95 each. — C-10 blank cassettes packaged in a
hard plastic box 10 pack $8 50 - 5 25" Diskettes sinale side double-density
soft sectored with hub nogs 10 pack only $18 00— add $2 per 10 pack
shipping for tapes and diskettes

Any three $9 95 tapes for $24 95 DEALER INQUIRIES INVITED

Add $1 00 per tape for shipping. Indiana res. add 5% sales lax Send Certified
Check, MO. Visa or MasterCard No with Exp Date

HEATH COMPUTER SERVICES

950 East - 52 South ' -

Qreentown, IN 4X936

Phone (317) 628/3130 CUE

CIRCLE 33 ON READER SERVICE CARD

pleasanjrees

PICK OF THE

GRAPHICS AtoZ\/

MemotechsHB^

FocWIOOO

. 3.DOrawing

• Shapes

. Animation

• M C listings
, pwit below

or to right
ot display'

, Graphic^

.Plot 3-D (owf^.
. uc control (speec

. ^disassembly
. New call add"***

PADS 2.49 ea

PROGRAMMING
FORM PADS

• All lines including edit hnes

Not hall sheei— full BVtori i

premium erasable paper

> 50 sheets per pad

• Free coded example of
WC Fields

• Window Card 'or easy readir

(+ .75padP&H)

16K

...I. — .7 ■ , ■■

irnilH h.

Zxak-man!

At last a version witti attention to detail Zxak
is a cute cubical character that winks and
chews as he moves 9 levels and 4 ghouls
make tor strategy game playing All in smooth
MC. animation. A must 14.95

16K
XON!

'81

1000

CltyofXon!

Scroi's 3 dimensionaliy Your shadow follows
below as you avoid hazards Various
weaponry help you rack up points Most
impressive graphics your machine can
exhibit InMC 19.95

Please add 1 50 per cassette postage & handling S*

pleasanjrees ^p

L3si.ru>

rrey

P*H

*f*tCC

ZXAK-MAN

14*5

1 »

CltyofXon

1»*S

l SO

BmmCon

I.H

1 »

•099*

12*5.

i so

Ptm

24S

Graphic* A-Z

17M

ppd

Time Rescue

Pilot a time skimer and rescue
ships stranded in time, but watch
out for time vortexes. $5. Add $1
and get Hyper-Carpet a simple pro-
gram using unusual graphics. All
Ruskat code is user accessible.

Ruskat

3824 E. Paradise Ln, #51

Phoenix, AZ 85032

Education Programs

UQuizU

Quizzes user on any information
that user enters. Option of respond-
ing to either a question or an
answer. Determines the user's
problem areas; periodically repeats
those questions. CC: $8.95 pp.

Bob Martin

15950 RobsonCt.

Fountain Valley, CA 92708

The Math Teacher

Educational math tutorial pro-
gram. Drills basics of +, -, • /.
First grade to junior high. 25 prob-
lems of user-selected operation.
Score, graphics, and option to do
another 25. CC: $29.95.

CompuTech

Dept. TS-MT-SYN

PO Box 7000-309

Redondo Beach, CA 90277

Shoot em Up Games

B-29 Bomber

Your mission is to destroy the
enemy tank. Two game options:
moving and nonmoving tanks. For
more information write:

E & S Software

PO Box 196

Budd Lake, NJ 07828

Artillery (SP-101)

Hit a target down range. Range
given in miles; you enter bullet
velocity and angle of elevation.
Points depend on distance of hit
from target. Trajectory visible. 4
levels of difficulty. $9.95; $1 s&h.

JPR Software

PO Box 4155

Winter Park, FL 32793

Space Games

Adventure in Space

Survive the trials of space travel;
all text adventure; first in a series.

Steve Dinstbier

1159W. TaftRd.

St. Johns, MI 48879

Casino Games

Roulette (SQ-103)

Computer chooses random num-
ber between and 36. You bet on
1 number, 2 numbers, 3 numbers,
high or low, odd or even, or a
dozen. Payoff according to odd for
bet. $9.95; $1 s&h.

Craps (SQ-102)

2 dice. Computer rolls and adds
the points. You bet on the roll.
$9.95; $1 s&h.

Blackjack (SQ-104)

Game of 21 played with 52 cards.
Computer shuffles and deals. Ob-
ject is to get 21. You may draw
additional cards. $9.95; $1 s&h.

Slot Machine (SP-102)

Las Vegas style game. 3 random
figures appear in the window. Start
with a generous supply of money;
play to increase it. $9.95; $1 s&h.

/?<?<taog(SQ-110)

Card game against the computer.
5 cards to a hand. Beat the top
card to win. Win amount bet plus
same from the pot. Lost bet goes
to pot. $9.95; $1 s&h.

JPR Software

PO Box 4155

Winter Park, FL 32793

Casino

Craps, Money Boxes, In-b-
tween, 1-6, Slot Machines, and
Horse Racing. CC: $4 each pp.
(money order)

Steve Dinstbier

1159 W. TaftRd.

St. Johns, MI 48879

Joysticks

ZX Joystick

Full details on adding a joystick
including fire button. Parts cost less
than $10. $3; legal size SASE

Micro Da et Fils

PO Box 7221 RR2

Gatineau, Que. .Canada J8P 6H8

RAMs/ROMs/
EPROMs

TS1000 64K RAM Module

Assembled in America. $109.95.
Allow 2-3 weeks for delivery.

Barlog Software

401 N. Geyer Rd.

Kirkwood, MO 63122

Power Supplies

Power Switch

Eliminates wear on power jack.
3.25 x 2 x 1 inch black case with
heavy duty rocker switch. $10; $2
s&h.

K. Roberts

PO Box 2202

Davidson, NC 28036

AC Surge protectors and EMI-RFI
Filters

A variety of products designed
for surge protection for computers
and computer equipment. Write
for full details.

Electronic Protection Devices

PO Box 673

Waltham, MA 02254 S

jmuuuijuuutufliufljur'iik,

CIRCLE 49 ON READER SERVICE CARD

September/ October 1983 ® SYNC

FOR
SINCLAIR

AND

TIMEX

SINCLAIR

OWNERS
ONLY

If you own a Timex Sinclair, a ZX81,
or any other Sinclair computer,
you've probably discovered that
the big microcomputer magazines
cover only the bigger computers.
Where can you find helpful articles on
the Sinclair? In Sync!

Sync is the one magazine that's
written exclusively about Clive Sin-
clair's marvelous inventions, the Sin-
clair computers. And it's the one
magazine to read if you want to get
more from your Sinclair.

You'll find program listings for
games, helpful programming tech-
niques, hardware upgrades, math and
science programs, news of new prod-
ucts for the Sinclair— in short, every-
thing you need to use and enjoy your
Sinclair to the fullest.

In just two recent issues, for exam-
ple, we covered:

□ Putting a Reverse Character in a
String

D How to Double Your Memory

□ Least Squares Data Analysis With
theZX80/81

□ Space Warp: A Graphics Space
Game

□ How to Reduce "Blank Screen
Time"

□ Storing Three-Letter Words in an
Array

□ Software Review: ZX Galaxians

□ An Introduction to Expression Eval-
uation

□ Short Programs Just for Fun

D The ZX81 Parser and User-Defined
Commands

□ Understanding Floating Point Arith-
metic

□ Handling Strings from Another Di-
mension

□ Book Review: Understanding Your
ZX81 ROM

□ How to Add a Keyboard to Your Sin-
clair

□ Translating Other Basics: DEF on
theZX81

n Six Outer Space Games— With Pro-
gram Listings

□ Hardware Review: Sinclair ZX Spec-
trum High Resolution Color/Sound
Computer

If you own a Sinclair microcom-
puter, Sync is the only computer mag-
azine you really need. Subscribe now
to Sync, and you can save up to 33%!
Just complete and return the post-
age-paid reply card or the coupon
at right.

SAVE UP TO 33%
ON SYNC!

SL-inc

CN 1986- Morristown, NJ 07960

VCCI Please send me
T CO! Sync for:

□ One year (6 issues) for $12.97—
I save 19%.

□ Two years (12 issues) for $22.97—
I save 28%.

D Three years (18 issues) for
$31.97-1 save 33%.

Savings based on full 1-year subscription price
ol $16.

Mr.
Mrs.
Ms

(please print lull name)

4S16

Address-

_Apt._

City_

^Zip-

State

CHECK ONE:

D Payment enclosed. □ Bill me later.

Otter valid In U.S. and possessions only Please allow
60 to 90 days lor delivery ol tirst issue

NEW SUBSCRIBERS ONLY

Directory of Publishers

Bernard Babani
The Grampians
Shepherds Bush Rd.
London W6 7NF
U.K.

Birkhauser Boston, Inc.
380 Green St
Cambridge. MA 02139
(617)876-2337

E Arthur Brown Co.
1702 Oak Knoll Dr.
Alexandria, MN 56308
(612)762-8847

CompuSoft Publishing, Inc.
535 Broadway
El Cajon, CA 92021
(619)588-0996

Computer and Electronic

Supply Services
PO Box 345. MIT Branch P.O.
796 Main St.
Cambridge. MA 02139

(617)491-8925

Computer Continuum

301 16th Ave.

San Francisco, CA 94118

Computer Engineering

Services
POBox 1222
Show Low, AZ 85901

(602)537-7522

Creative Computing Press

39 E. Hanover Ave.

Morris Plains, NJ 07950
800-631-81 1 2 (orders only)
(201 (5400445 (in NJ)
Note: Visa/MC/AE. Write for

free catalog. Outside U.S. s&h

is $3 per order; shipped airmail

only.

Data Assette
56 S. 3rd St
Oxford, PA 19363

800-523-2909

(215)932-4807

Dell Publishing Co.
2245 East 47th St.
New York, NY 10017

Dilithium Press

8285 SW Nimbus, Suite 151

Beaverton, OR 97005

(800)547-1842

(503)646-2713

Granada Publishing
515 Madison Ave.
New York, NY 10022

Wayne Green Books
Route 101 W.
Peterborough, NH 03458
1-800-343-0728

J. L. Hartwell
540 Haskins Rd.
Bowling Green, OH 43402

Jenn Products

Box 246

Harrison, ME 04040

Fred Johns
Alpha Electronics
935 North Blvd.
Alpha, NJ 08865

K.D.V.H.E. Publishers
PO Box 6788
Chicago, IL 66080

McGraw-Hill Book Co.
1221 Avenue of the Americas
New York, NY 10020
(212)997-3071

Melbourne House Software
Dept CS

347 Reedwood Dr.
Nashville, TN 37217

Micro Design Concepts
PO Box 280
Carrollton, TX 75006

Microscene

6 Battenhall Rd., Harbome
Birmingham
U.K. B17 9UD
Para Publishing
PO Box 4232-88
Santa Barbara, CA 93103-0232
(805) 968-7277

Oxford Computer Pub.
R. L. Associates
614 W. Manchester Blvd.
Ingle wood, CA 90301
(213)671-6667

Para Publishing
PO Box 4232-91
Santa Barbara, CA 93103-0232
(805)968-7277

PC Clearinghouse, Inc.
11781 Lee Jackson Highway
Fairfax, VA 22033
(800) 368-4422

Prentice-Hall, Inc.
Englewood Cliffs, NJ 07632
(201)592-3082

Que Corporation
7960 Castleway Dr.
Indianapolis, IN 46250

1-800-428-5331 (orders)

(317)8442-7162

Research Press, Inc.

Box8137-P

Prairie Village. KS 66208

Redditch Electronics
21 Ferney Hill Avenue
Redditch, Worcs
U.K. B97 4RU

Reston Publishing Co.
c/o Prentice-Hall, Inc.
320 Hudson Ter.
Englewood Cliffs, NJ 07632
(201)592-2018

St. Martin's Press
175 Fifth Ave.
New York, NY 10010
(212)674-5151

Softest

10 Richmond Ln.
Romsey, Hants
U.K.
Romsey 513676

Sybex, Inc.
2344 - 6th St.
Berkeley, CA 94710
(415)848 8233

Tab Books Inc.
Monterey Ave.

Blue Ridge Summit, PA 17214
(717)794-2191

TSG Enterprises
54 Richmond PI.
Denville, NJ 07834

V and H Computer Services
182c Kingston Rd.
Staines, Middlesex, U.K.
Staines 58041

John Wiley & Sons, Inc.
605 Third Ave.
New York, NY 10158

Yes! Bookshop
1035 31st St., N.W.
Washington, DC 20007

(202) 338-7874 %

September/October 1 983 « SYNC

A complete line of software and books for Timex Sinclair computers
from Reston Publishing Company, A Prentice-Hall Company.

TimeWare Software
□ Strategy Pak (R0705-5)(R7695-1)

$19.90

TIMEWARE CHESS

This game has received rave reviews from everyone who has played
It. Now is your chance to see if you can beat your Timex Sinclair
computer in an exciting game of chess.

CASINO PAK 1: One-Armed Bandit/Blackjack

Your Timex Sinclair computer is your tickei io a furi-packcd p.igh'
out in Las Vegas. Be prepared to win big on the One-Armed Ban-
dit, or, match wits with the computer dealer in Blackjack.

□ Fantasy Pak (R4608-7) (R3296-2) (R1761-7)

MONARCH! H

In this interactive game your Timex Sinclair computer is your cas-
tle. You are in control of the kingdom. If you have what it takes
to be king, you can keep your crown. If not, you lose your throne.
Features Fastload—2 minute loading!

INVASION FORCE

Protect yourself from a giant alien ship by breaking through the
force field to get a clear shot. But watch out! You must also con-
tend with waves of smaller ships that protect the mother ship.
Features Fastload—2 minute loading!

ESCAPE FROM SHAZZAR! An adventure game!
Find the temple! It's your only escape! On your journey uncover
as much treasure as you can, and find the right keys to get through
the doors. But, avoid the deadly fumes, poison, magic, cave-ins,
bottomless pits, and more! Get to the Temple and locate the
thruster!

Lj Nowotnik Pak (R1261-8)(R4953-7) $19.90

TimeWare Books

] Mastering Machine Code on Your ZX-81 by

Toni Baker (R4262-3) $18.95
] The ZX-81 Pocket Book by Trevor Toms

(R9525-8) $18.95
] 49 Explosive Games for the ZX-81 by Tim

Hartnell (R2087-6) $17.95
1 The Explorer's Guide to the ZX-81 and Timex
Sinclair 1000 by Mike Lord (R1815-1) $17.95
Q Fifty 1K/2K Games for the ZX-81 and Timex
Sinclair 1000 by Alastair Gourlay, James
Walsh and Paul Holmes (R1979-5) $16.95
r~l Making the Most of Your ZX-81 by Tim
Hartnell (R4189-8) $16.95

SELF-TEACHING SOFTWARE FOR THE ZX-81
and TIMEX SINCLAIR 1000

by Joseph R. Gladstone

Children from grades 1 through 6 will find basic arithmetic
skill instruction and numerous practice programs. Each of
the six packages contains 2 cassette tapes with 32 lessons,
games and activities, plus an explanatory booklet. This
newly designed classroom aid comes handsomely pack-
aged in durable vinyl binders. Six units, each soid sepa-
rately. Features fastload—2 minute loading.

□ 1 (R6966-7) $29.95

□ 2 (R6967-5) $29.95

□ 3 (R6968-3) $29.95

□ 4 (R6970-9) $29.95

□ 5 (R6971-7) $29.95

□ 6 (R6972-5) $29.95

Choose new TimeWare books or new TimeWare
game software . . . even TimeWare self-teaching
aids for children. All new, and conveniently
available by mail!

Order your new TimeWare books
and software paks today!

The NOWOTNIK PUZZLE by David Nowotnik

Watch your computer take a simple pattern and scramble it on the
screen. Then the challenge begins! You have to return the puzzle
to its original pattern.

DEMOLITION /TEN-PIN by David Nowotnik

Two great games on one cassette! In DEMOLITION it's up to you
to stop the moving wall before it reaches the top of the screen. Or,
convert your computer into a bowling alley. Your score depends
on how hard and accurately you send the ball down the alley.

Each new book and software pak can be used on your ZX-81, Timex Sinclair 1000 or the new Timex Sinclair
1500. Many of the software paks offer the modern 2 minute loading feature.

Just note your choices on this order form and mail the whole page or a copy of it to us at the address below.
A check or money order, for the total amount, plus your state's sales tax, included with your order will save
you money! The publisher will then pay all postage and handling charges.

Ship my order to:

Name . —

Address

.City.

State

Or, charge your order:

Signature

Visa Mastercard Account *_

.Exp. Date_

Zip_

Reston Publishing Company c/o PRENTICE-HALL, Inc. Book Distribution Center Rte. 59 at Brook Hill Drive West Nyack, NY 10995C

Time

Or call toll-free: (800) 336-0338

V-09U-9C (3)

CIRCLE 53 ON READER SERVICE CARD

SYNC at the Library

TS1000/ZX81 Books

This section contains books specific to
the Sinclair and Timex Sinclair com-
puters. The entries are arranged alpha-
betically by publisher. The entries from a
given publisher are arranged alphabeti-
cally by title. See the "Directory of Pub-
lishers" for the publisher's address.

The book titles may refer to the ZX81
or the TS1000, but the contents will apply
to both machines. If you have an unex-
panded ZX81 , you may not be able to use
some of the program in books developed
specifically for the unexpanded TSIOOO
which take advantage of the 2K RAM on
board. If you have a TSIOOO, you can use
any of the books written for the unex-
panded ZX81. If you have a RAM pack,
you should have no problems either way.

Most publishers will accept mail orders,
but there is usually a shipping and hand-
ling charge either per book or per order.
Your local bookstore or computer store
will be able to get the books of your
choice if they are not carried in stock.
You should confirm prices and shipping
charges before making your order. This
Book Buyer's Guide is not a catalog and
we cannot guarantee either the accuracy
or timeliness of the information. It is
intended to acquaint you with the wealth
of book resources available for your com-
puter.

Bernard Babani

The Art of Programming the IK ZX81.
By M. James and S. M. Gee. £1.95.

Programs that fit into the IK machine.
Random number generator; graphics;
games of skill; PEEK and POKE; digital
clock and reaction timer: character
strings. 96 pp.

The Art of Programming the J6K ZX81
By M. James and S. M. Gee. £2.50 plus
s&h.

Use your 16K RAM pack and printer.

Explains how the extra storage space is
used, covers some utilities useful in writ-
ing longer programs, games illustrating
the extended graphics capabilities in 16K,
writing and debugging longer programs,
introduces programs for editing data
bases and statistical analysis, and using
randomness. 136 pp.

Birkhauser Boston, Inc.

Machine Code and Better Basic
By Ian Stewart and Robin Jones. $1 1.95
This book introduces structured Basic
programming, and machine code. Sam-
ple programs include: a complete word
processor, enqueuing and dequeuing
data, and French vocabulary testing.
Code routines include: turning the dis-
play into inverse video, adding and mul-
tiplying, moving data around in RAM.
Applies to both the TSIOOO and TS2000.

Timex Sinclair 1000: Programs, Games,
and Graphics.

By Ian Stewart and Robin Jones. $10.95.
A lighthearted but serious-minded in-
troduction to Sinclair Basic. Includes:
setting up the hardware, saving pro-
grams on tape, looping and branching,
graphics, logic, keyboard control of pro-
grams, character manipulation, sub-
routines, debugging techniques.

E. Arthur Brown Co.

Graphics A-Z. $19.95.

Complete graphics course for the
TS/ZX computers. Chapters on the
Memotech High Resolution Graphics
module. Topics: animation, 3-D plotting,
diagonal scrolling, writing and dissecting
uneditable programs, machine code short
cuts, and more. Program listings.

The Timex Sinclair Directory. $5.95.

Where to find practically everything
for the TSIOOO and ZX81. 90 double
column pages with complete descriptions

and photographs of memory expansion,
keyboard, mass storage, printer, modem,
control circuitry, miscellaneous systems.
Software from games to serious business.
Directory of suppliers.

ZX8I Basic Book. $12.95.

An improved replacement for the
ZX/TS operating manual. Gives com-
plete instructions. Cover the topics in
much greater detail in an easier to under-
stand writing style. All instructions are
followed by examples of actual use.
Strings, arrays, and DIM statements.

CompuSoft Publishing, Inc.

Learning Timex Sinclair Basic for the
Timex WOO and the Sinclair ZX81.
By David A. Lien. $14.95.
ISBN 0-932760-15-5

Easy to understand Basic tutorial writ-
ten specifically for the TS/ZX computers.
Leads the user from "turn on" to
"advanced programming" with a compre-
hensive style. 352 pp. 7x9. Paperback.

Computer Continuum

Projects plus Applications Manual
$10.

Booklet for use with the Buffered Bus
but the designs can be interfaced directly
to the computer with some considera-
tions. Includes construction techniques,
8255 programmable port control and
counting applications, A/D, Digital
oscilloscope program, EPROM pro-
grammer.

Computer Engineering Services

Neat Stuff for Your Sinclair
1K/16K RAM. $8.95 plus $1.25 s&h.

An edited book of some of the finest
and most useful subroutines and programs
available for the Sinclair user. It has some
of the simplest and most wanted hardware
additions that anyone can build and
install. Softbound.

September/October 1983 • SYNC

IMOW.ATS1000/ZX81

PUSH-BUTTON

KEYBOARD

FOR UNDER $20.00.

E H S

If BPW PQKi »*>*<

I III 1 H

go** aua ia!LL

COti XtK' MfcS-

an ■ n n n pa
9 9 SH H a

- ; Tq*:. ■-.■■■

At last there's a really cheap but
efficient way of ironing out theTS1000/ZX81's
only real bug: its keyboard. The Filesixty
Buttonset offers

■ A full-travel calculator-type moving
keyboard for only $19.50.

■ Installed in seconds. The peel -off
adhesive backing means you just register into
position and press.

■ No messy labels, dismantling or
soldering.

■ 3 groups of colour keys to pick out
shift, numerals and newline.

■ Precision moulded in ABS to match
your TS1000/ZX81, with contrasting legends
for maximum legibility.

Orders to Filesixty Ltd . P.O. Box 1469, Murray Hill Sta .,
New York, NY 10156

'^i

; is clean
^ tion

3 So all you do is remove the
prot^

2 The ^

Cheques/money orders made payable to Filesixty Ltd.
Please send me

(qty.) Buttonset(s)

at $19.50 each (inclusive of postage & packaging).

Total $ BLOCK CAPITALS

Name

(U.S. DOLLARS ONLY)

Address

State
Zip—

FILESIXTY i

CIRCLE 31 ON READER SERVICE CARD

The Expandable ZX80 and ZX81,
T/S1000 Too!
$9.95 plus $1.25 s&h.

The book for the electronics hobbiest
to enable him to add memory, music,
speech and a whole lot more. Softbound.

Creative Computing Press

The Best of SYNC, Volume 1

Edited by Paul Grosjean. $9.95 plus $2

s&h.

A collection of over 80 of the most
valuable articles, programs, tutorials, and
reviews that appeared in Volume 1 (1981)
of SYNC Magazine. A vital resource for
users of the TS1000, ZX81, ZX80 with
8K ROM, ZX80, and MicroAce com-
puters. Topics include: games, math appli-
cations, graphics techniques, program-
ming tips and tutorials, translation from
other Basics, machine language program-
ming, hardware, reviews, glossary of com-
puter terms.

Computers for Kids (Sinclair Edition)
By Sally Larsen. $4.95 plus $1 s&h.

Written specifically to introduce child-
ren 8-13 years old to the ZX81. Requires
no previous knowledge of computers,
algebra, or variables. Enables the child to
program a ZX81 in less than an hour.
Includes a section for parents and
teachers. 56 pp.

Fiftv Programs for the Timex Sinclair

1000

By Leland B. Carter. $6.95 plus $2 s&h.

This book features 50 program listings
which the TS1000 users (beginners on
up) can type into their computers directly
and and run. listings include: games, puz-
zles, mathematical calculations, filing pro-
grams, graphics programs, calendar and
more. No knowledge of Basic required.

The Gateway Guide to the ZX81 and

ZX80

By Mark Charlton. $9.95 plus $2 s&h.

Practical programming manual for the
beginner with the TS1000, ZX81, or
ZX80. Furnishes over 70 fully docu-
mented programs. The majority have
been written for easy conversion from
machine to machine (ZX81 to ZX80 and
vice versa). Describes each function and
statement, illustrates it with a demonstra-
tion routine or program, combines it with
previously discussed material. 172 pp.

Getting Acquainted with Your ZX81
By Tim Hartnell. $9.95 plus $2 s&h.

Contains more than 70 programs to
help the reader get the most from his
TS1000 or ZX81. Game programs
include: Checkers, Alien Imploders,
Blastermind, Moon Lander, Breakout,
Star Burst, and Derby Day. Programs for

FLEXIBLE
RIBBON

CONNECTOR

for RAM

COMPUTER

5V4" FLOPPY DISC INTERFACE

Shugart compatible 43K

formatted

5V4" DISC DRIVE

IIMDESCOMP

from

P.O. Box 2288
Redmond, WA 98052

KEYBOARD— No soldering,
has On/Off switch, internal
and external RAM connectors,
sculptur ed keys. Computer fits

inside, using only a

screwdriver.

OS SOUND GENERATOR

16 Internal records, 3
tone gens., 5 octaves,
amp. output, vol. pot.

CENTRONICS INTERFACE
CENTRONICS CARLE

OS HIGH-RES GRAPHICS CONTROL

256 x 192 pixels. Statements — Move
X,Y; Plot X.Y; Black; White; Clear;
Print A$; Up; Down; Left; Right;
Box X,Y; Scroll; Copy.

OS PROGRAMMABLE CHARACTER GENERATOR

Up to 128 characters, switches between stan-
dard characters and yours. 8x8 square CHRS
program included

CIRCLE 59 ON READER SERVICE CARD

cascading sine waves, plotting graphs and
tables, data sorting, equation solving, plus
the use of PLOT, SCROLL, PRINT, TAB,
PEEk, POKE, and much more. 120 pp.

The Timex Sinclair 1000 Ideabook
By David H. Ahl. $6.95 plus $2 s&h.

50 ready-to-run educational programs
demonstrate scores of different tech-
niques for solving problems in mathe-
matics, science, and business. 10 chapters
deal with solving problems by formulas
and repetitive trials, convergence, recur-
sion, compounding, probability, geom-
etry, science, simulations, and drill and
practice. Some problems demonstrate the
capabilities of the computer; others iden-
tify its shortcomings. 152 pp.

The ZX81 Companion

By Bob Maunder. $9.95 plus $2 s&h.

For both ZX81 and TS1000 users.
Assists in four applications areas: graph-
ics, information retrieval, education, and
games. Contains scores of fully docu-
mented short routines plus complete pro-
grams. Disassembled listing of the ZX81
ROM monitor. 132 pp.

Katie and the Computer

By Fred D'Ignazio and Stan Gilliam

$8.95 plus $2 s&h.

Explains to a child how the computer
works. Katie falls into the land of
Cybernia inside her Daddy's computer.
Her journey parallels the path of a simple
command through the stages of pro-
cessing. She encounters the multi-legged
and mean Bug who lassos her plane and
spins her into a terrifying loop. Supple-
mentary information on computers, bytes,
hardware, and software. For 4-10 year
olds.

Be a Computer Literate

By Dr. Sylvia Charp and Marion Ball

$6.95 plus $2 s&h.

Uses tasks like mowing lawns, issuing
paychecks, and controlling traffic lights
to introduce basic computer concepts. A
light-hearted informative text tells about
the kinds of computers, what goes on
inside the machine, the language of the
computer, and how computers work for
us. The problem of averaging class grades
is used to show how to write a simple
program. For grades 5-9.

Data-Assette

The Microcomputer's User's Book of

Tape Recording

$9.95.

Excellent book explaining how to set
up your recorder to achieve reliable re-
sults. The book discusses problems that
arise and explains how signals are re-
corded. Coupled with the Vu Meter and
Test and Alignment Tape, many hours
of frustration can be saved.

September/October 1983 SYNC

WANT TO BUILD YOUR TS1000 INTO A REAL COMPUTER?

BASICARE Microsystems — A family of identical modular units which measure 7.3"x3.4"x.S". The
units, which stack on top of one another to build a complete system, may be configured to the user's
individual needs.

PERSONA — Connects to the rear of the computer with a flexible cable and acts as the interface for
the other modules. This module, and the others which stack on it, is exceptionally attractive. Neither
drawings nor photos do the system justice. It buffers all the computer's signals via the ribbon cable.
It then talks to the other modules through a 64 pin ORGANIC BUS. Other modules respond when
PERSONA sends their individual SLOTS signals along the bus $59.95

RAM 16 — 16K memory which can be expanded later $49.95

RAM 64 — Arranged as 4 blocks of 16K; all can be used under MINIMAP control. On board address
decoding allows simultaneous use of many RAMs with MINIMAP $139.95

MINIMAP — A mapping device which can expand address space to as much as 1 megabyte. When used
with RAM 64 (from 1 to 16 RAM 64s) space is organized into vertical 64K pages. These pages are
divided into SEGMENTS labeled: ROM, TOOL, FILE A, DATA, PATH, SLOT, FILE B. It is possible
to have many BASIC programs, and several TOOL and DATA SEGMENTS, distributed among different
PAGEs $55.95

PERICONa — General purpose, user programmable 24 lines of input/output. Up to 4 PERICONa can
be used together $51.95

PERICONb — 24 lines of heavy duty output to access and control the outside world. Lines are capable
of operating relays or driving long signals. Up to <» c?n he "s«1 $54.95

PERICONc — Centronics printer interface $69.95

CENTRONICS CABLE $29.95

Other modules available — ROM, GRAPHICS, A-D, D-A, Defineable characters.

USING THREE OR MORE OF THESE UNITS REQUIRES A
HEA VY DUTY POWER SUPPLY.

SWITCHED OUTLET BOX — One outlet is offset and switched for use with your
power supply. This allows you to turn your computer on and off without disturb-
ing peripherals $19.95

HEAVY DUTY POWER SUPPLY - 9V with ON/Off switch. Much more powerful
and cooler running than the standard power supply $24.95

PAGE SEGMENTS

m m W "V- w *» ** a* * V *

SINCLAIR PLACE "COMPACT" KEYBOARD

10W" x 7" x 1'/," (Max.)

FULL FUNCTION
KEYBOARD

VERY POSITIVE ^^^^^^^^

FEEL AND SOUND

2 SHIFT KEYS

NUMERIC KEYPAD

SPACE BAR

METAL CASE—
Fully Shielded!

Single stroke keys: DELETE,

STOP, EDIT and

FUNCTION.

SHIFT keys are BLUE with blue legends for shifted operations. FUNC-
TION key is GREEN with green legends for function operations. DELETE,
STOP and EDIT keys are RED. NUMERIC keys are BLUE. Other keys
and legends are BLACK. Case is grey. Nothing to solder on, paste on, cut
or drill. Only a screwdriver is needed to fit the computer inside the keyboard.

$88.80

Z-EXCHEQUER

THE KLUTZ-PROOF BANKING PROGRAM

The best documented, easy to use, banking program you'll find. All you
need to know is how to load a tape into your machine and follow SIMPLE
directions. Do deposits, checks, charges, debits, automatic teller transac-
tions, reconciliations, etc., 26 categories for checks and deposits. Easily
modified, if desired, Simply PRINT command for hard copy.

$20.00

All products guaranteed. We will replace if there are defects. All payments
must be in U.S. dollars. Add $2.00 for third class shipping and handling,
in continental U.S. Add $3.00 for first class or Hawaii, Alaska, Canada.
VISA and MASTERCARD add 3%. Washington residents add 8% tax.

cooo

ROM

•K Computer BASIC Inter-
preter and operating
ayatem.

TOOL

I6K) Machine coded routines
or data storage.

RLE A

(16K) Normal residence of
BASIC programs.

DATA

(UK) Used lor extra data
space or storing long
BASIC programs.

PATH

(4K) Not presently used.

SLOT

|4K) Used In conjunction with
other peripherals.

FILES

(16K) Used for display but can
be used for BASIC II no
display Is used.

MINDWARE

THIS TAPE UflS
FREPFIRED BV THE

tin- tee.

MW-100 SIDEWINDER PRINTER - Connects directly to back of the com-
puter. Impact dot matrix. Uses standard \W wide paper roll rather than
special, treated paper. Prints 16 character wide line. No command or hard-
ware modifications required to use this printer! 3 modes of printing — MODE
0: Prints each 32 character screen line consecutively on 2 printer lines. MODE
1: Divides screen lines at center and prnts left side first, then right side.
By taping the halves together you get 32 character line printouts. MODE
3: Prints 16 character lines from screen when screen information is only
16 characters wide. RAM pack and other addons can be attached behind
the printer. No interface required.

SPECIAL

$85.00

REPEAT KEY MODULE — Solders inside case — repeats as long as you
hold key $15.00

INVERSE VIDEO MODULE — Solders inside case, permits normal black
on white or white video on black $15.00

DEALER INQUIRIES WELCOME!

SiwcGafo ^ace

P.O. BOX 2288 • REDMOND, WA 98052

CIRCLE 58 ON READER SERVICE CARD

30 Programs for the ZX81
By Richard Altwasser. $9.95.

From the Cambridge Collection are
30 programs for the TS1000 and the
ZX81. These programs are written for
the unexpanded IK or 2K machine.
Entertainment and learning from one of
the designers of tomorrow's systems.

Dilithlum Press

Control Things with Your Timex Sinclair.
$6.95.

Put your TS1000 to work. With a few
inexpensive parts, measure the outside
world automatically— light, heat, weight,
and more. Turn on lights remotely. Add
audible alarms and other sounds to your
computer's repertoire. Time events. Add
a real keyboard and/or a joystick.

How to Use the Timex Sinclair. $3.95.

Authors assume you know nothing
about computers in general or the TS1000
specifically. They tell you what to expect

Extend your ZX81/TS1000:
Add Memory that won't Forget!

y ADD YOUR OWN SYSTEM UTILITIES

^ BUILD UP A LIBRARY OF MACHINE
LANGUAGE SUBROUTINES

y UP TO 8K NONVOLATILE RAM

USE HM61 1 6LP CMOS RAM *
OR 2716/2732 EPROM

y COMPATIBLE WITH
16K RAM PACKS

29 95

plus Si 95 shipping and handling

^ READ THE REVIEWS

What a super product 1 conceived and executed very nicely and wtih quality compor >

(SYNTAX QUARTERLY Winter 82)

8K Nonvolatile memory is a gem' li has so many possible uses I recommend this board mosl heartily

(OKLAHOMA S.U.G. Newsletter 1/3)

We lound the documentation to be far superior to that (of) most hardware we've rei

(SUN Newsletter Nov/Oec 82)

For versatility this is even better than an EPROM ranks quite high on the list of

(SYNC Magazine Mar/Apr 83)

INTRODUCTION

This memory board is designed to fill the transpai
block of memory (from 8 to 16K) in a ZX8M6K
This area of memory is an ideal place to slore, eilher per-
manently or temporarily machine language roul
data which are to be used by the BASIC system

A sample display routine, a program — merging routine
and procedures for storing utilities on tape are included
with the kit

The use ol HM6116LP 2K CMOS RAM memory N
their own reserve power supply means that routines Stored
m the RAM are nonvolatile — the RAM retains its memory
even when the ZX81 is switched off or resel More
■ ng RAM the routines you store in the memory are easily
modified The iilhium cell supplied with the board will main-
tain sufticie'

ASSEMBLY

Complele step-by-step instructions in a 20 page manual
make a board easy Construction takes be-

jred above) is
i solder-masked printed cir-
cuit board all capacitors, res » stors. sockets
tors, mtegraled circuits, and the lithium i i

- I ',M\ »', 6116) P I HAM i!

will accomodate three more lor a total of 8K

Compu ■'■ $29 95

$1600

$1305

: .vi!h 2K $44 95

«ith8K $59 95

Shipping -. $ 1.95

■ ■ - :.:■■■

HUNTER, 1630 FOREST HILLS DRIVE, OKEMOS, Ml 48864
CIRCLE 34 ON READER SERVICE CARD

and how to handle the problems you will
encounter. You learn how to set up the
computer, how to make it work, where to
buy accessories and software, and where
to get additional information. Practical
advice while steering away from technical
tidbits.

More Real Time Applications for the
TS1000/2000. $12.95; with software:
$24.95.

Provides you with some ready to use
programs and gives an insight into the
techniques on which software is built. Full
documentation and detailed commentary.
Programs include: Dif, Till, Statistics,
Cricket, Carbon Dating, Half Life, Re-
actions, Gas Laws, Doppler, Triangle,
Peristalsis, Electrolysis, Spider Invaders,
Notes, Music.

The Secrets of Using the Timex-Sinclair.
By Jerry Willis. $3.95.

Provides an introduction to the com-
puter's basic components; an overview of
the things you can do with it; step by step
instructions on how to set it up; LOADing
and SAVEing; introduction to Basic; in-
formation on how to select, buy, install,
and use popular accessories; sources of
information about your computer such as
magazines, books, and users groups. 124
pp.

The Sinclair ZX81. $11.95; with software:
$24.95.

Practical programs to do real jobs in a
variety of environments. Includes: bulk
storage, word processor, financial appli-
cations, banking uses. Author pushes the
ZX81 and casts aside the idea that it is
too small for any real computing work.

32 Basic Programs for the Timex Sinclair
Computer. $19.95; with software $34.95.
Games, graphics, education appli-
cations and practical uses. Purpose of the
program is described and how to use it is
explained. Sample run and complete pro-
gram with suggestions for changes. Main
routines and variables listed.

Using and Programming the Timex Sin-
clair Computer. $9.95.

An introduction to programming the
TS1000. Complete education in Basic
along with neat tricks in Basic appli-
cations. Machine language introduced.

Wayne Green Books

Converting to Timex/ Sinclair Basic: A
Guide to Translating Basic Programs.
By Stuart L. Bird. $14.95.
ISBN 0-88006-063-8

Teaches readers how to translate Basic
programs written for other Basics to run
on the TS/ZX computers. Contains a
description of each statement and an ex-
ample of its use. Differences among state-

September/October 1983 «= SYNC

merits and various Basic dialects are
covered. Over 130 Basic instructions (200
including synonyms) are discussed.

Using the Timex/ Sinclair 1000.
By Ralph M. Coletti. Price: TBA.
ISBN 0-88006065-4

For those who have mastered the users
manual and want to go on. Programming
techniques include how to save memory,
how to translate into TS/ZX Basic Pro-
grams with home, business, educational,
and scientific applications are provided
with descriptions and suggestions on how
to adapt them. Hardware modifications
are also discussed.

J.L. Hartwell

Using Your Timex/Sinclair

Microcomputer

By J. L. Hartwell. $6.95 plus $1 s&h.

Why not unleash the potential of your
personal computer? This publication
goes a step beyond the basic program-
ming manual supplied with the comput-
ers. It is not meant as a substitute for the
owner's manual, but contains informa-
tion which clarifies and expands upon
concepts introduced in the manual.
Learn how to translate programs from
standard Basic into the Sinclair dialect.

Jenn Products

Fifty Nifty Programs for Your ZX81
IK RAM. $9.95.

For the unexpanded ZX81. Written in
Basic to facilitate learning; complete
instructions. Packaged in an 8/4 x 11
spiral bound format which lies flat for
convenient referral, these programs fea-
ture a variety of graphics and are mostly
of the game/activity nature with a few
utilities.

Fifty Programs for the Timex Sinclair

1000

2K RAM. $9.95.

For the unexpanded TS1000, all 50
programs are in Basic with many user
friendly statements to facilitate learning.
Featuring plenty of graphics, the pro-
grams are mostly games/activities with a
few utilities. All listings come complete
with instructions and are packaged in an
8 '/ 2 x 1 1 spiral bound book which lies
flat for convenient referral.

Fred Johns

Trouble-shooting and Repairs for Your

ZX81.

By Fred Johns. $4 plus $1.50 s&h.

Shows how to diagnose problems and
make repairs; trouble shooting tips to
shortcut diagnosis; diagrams of where to
check. DC readings throughout the board.
Some test programs. Where to buy parts.
List of tools needed, especially a good
volt/Ohm meter and LED tester. About
25 pp., 8 1/2x11.

September/October 1983 « SYNC

K.D.V.H.E. Publishers

Sinclair ZX81/Timex Sinclair 1000 Sta-
tistics: Twelve 16K Programs Including
Multif actor Analysis of Variance.
By A. H. Wolach and M. A. McHale. $11;
cassettes: $15; individual programs:
$1.50.

Twelve programs for statistical analysis
using t-test and analysis of variance. Ex-
tensive directions for entering data; com-
plete example of data input and output
for each program; large data sets can be
handled with 16K RAM. Tests include:
independent groups t-test; correlated
measures t-test; one, two, and three way
analysis of variance and more. 200 pp.

McGraw-Hill Book Co.

Basics: A Guide to the Timex/Sinclair

1000.

By Henry Mullish. $9.95.

Introduction to programming that
shows readers how powerful and flexible
Basic is while working at their own pace.
Applicable to the TS1500.

Bogglers: 22 Smart Games Programs (2K
to 16K) in Timex/Sinclair Basic.
By Graham Charlton, Mark Harrison, and
Dilwyn Jones. $12.95.

Entertainment and utility programs for
any TS/ZX machine with 16K RAM.
With more memory to work with the
programs are more challenging. The pro-
grams are fully tested.

Crunchers: 21 Simple Games for the

Timex Sinclair (2K).

By Henry Mullish and Yin Chiu. $8.95.

Fully explained game programs written
expressly for the TS1000. Games of
chance and skill written in Basic. Hours
of family entertainment as well as infor-
mative introduction to programming. Ap-
plicable to the TS 1500.

GOSUBS: 100 Program-Building Subrou-
tines in Timex/Sinclair Basic.
By Edwin and Shirley Gaby. $9.95.

A library of programming subroutines,
fully tested, immediately usable in larger
programs. For TS1000, 1500. and 2000
series (with minor modifications described
in the book).

Science and Engineering Programs for
the Timex/Sinclair 1000.
By Cass Lewart. $13.95.

25 professional programs for the
TS1000 with 2K RAM. Written for the
engineer, scientist, or college student.
Covers problems in electrical engineering,
number theory, computer science, prob-
ability, statistics, and operations research.
Programs solve, i.e., complicated queuing
and reliability problems, find solutions to
transcendental and differential equations,
find best fitting Lagrange polynomials and
work with complex numbers.

ZX81/TS1000 Programming for Young

Programmers.

By Linda Hurley. $9.95.

Affords young people the satisfaction
of getting hands on the machine imme-
diately and of running programs from the
very start. The book is in two colors and
has color coded programs. Applicable to
all Timex computers.

Melbourne House Software. Inc.

The Complete Sinclair ZX81 Basic

Course (25895MY)

$34.50.

A comprehensive manual designed to
teach you to write and develop Basic
programs for the TS1000 and ZX81; no
other books or aids are necessary. Easy
step-by-step guide with programs and "test
yourself" exercises throughout. Every
concept and function is fully described
by simple programs. Over 100 programs
and examples. Reference work for exper-
ienced programmers. By Beam Software.

Basic Course Cassettes (26490MY)
Two cassette pack: $7.50.

Contains some of the major programs
of the Basic Course manual above includ-
ing games, puzzles, and programming
hints and tips.

The Ins and Outs of the Timex TS1000 &

ZX81

By Don Thomasson.

11 lllvaiuauil Sv'UiCC

of in!

Armi

tion

on the hardware aspects of the TS1000
and ZX81. Complete circuit diagram. Full
discussion of the unorthodox methods
used to put the components together and
how they work. Projects to demonstrate
the potential of the computer included.

Not Only 30 Programs (26025MY)
By Melbourne House. $9.95.

Gives Not Only 30 fully debugged pro-
grams which will fit into the IK RAM of
the ZX81 (and also the TS1000), but also
a detailed explanation of how to write
your own exciting programs. Includes:
Star Wars, Lunar Lander, Black Jack, and
Adventures. Aimed at beginners.

Machine Language Programming Made
Simple for Your Sinclair and Timex
TS1000 (25957)
By Melbourne House. $14.95.

Go beyond Basic into machine lan-
guage programming and open computer
horizons you never thought possible.
Learn how to use the computer's own
language and find out about PEEK and
POKE. Programming techniques, hints,
and tips. Aimed at beginners. 120 pp.

The Complete Timex TS 1000 /Sine lair
ZX81 ROM Disassembly (20922M)
By Dr. Ian Logan and Frank O'Hara.
$19.95.

Examines all the routines in the ROM
and comments on each. Part A covers
addresses OOOOh to 0F34h which include
all the functions except for the floating
point calculator. Part B covers all the
routines involved in the "evaluation of an
expression" and a detailed explanation of
the "floating point calculator." For the
experienced programmer.

Understanding Your ZX81 ROM

(25913MY)

By Dr. Ian Logan. $14.95.

Illustrates all the facilities of the ZX81/
TS1000 monitor, how it works, and how
you can use it in your own programs. A
section on machine language use and sub-
routines will add to your programming
power. For advanced beginners to exper-
ienced.

Micro Design Concepts

Timex Sinclair Sourcebook. 96 pp. $6.95
plus $1.25 s&h ($2.50 s&h for outside
U.S.).

BEST KEYBOARD AVAILABLE!

surname m.""

• ■•■•"-"

-T« iff F

SUNKD-81

For Your
ZX-81/TS-1000

□ Includes Shielded Case
Fully Warranted For 90 Days
□ Now In Stock

Hundreds of Satisfied Customers

NEW LOWER
PRICE

If you're tired of not knowing whether your data got entered or tired of poking data in with one or
two fingers, then it's time to upgrade your ZX-81 to a full size, professional keyboard.

KD 81 FEATURES

• Full size keyboard with 41 keys

• Two color silk screened key tops for easy
- reading

• Key tops have commands and graphics
spelled out the same as ZX-81

• Extra shift key for real keyboard style typing

• Full size space bar

• Allows touch typing

• Rear cutout allows any RAM or

DEALER INQUIRIES WELCOME
expansion module to be plugged in

• Keyboard comes with own cables

• Keyboard case holds both keyboard and
computer with room to spare

• High impact plastic case with vaporized
metal shielding

• Easy assembly - no soldering, no
modifications

•Measures 10 4 'x7 ,"*27'

SAMWOO MONITORS GIVE YOU A BETTER PICTURE

SAMW00 provides a much better picture for your Sin
clair Computer than your TV monitor. Simple modifica
tion procedure includes easy-to-follow instructions.

Green $121.00

Orange 125.00

Green $130.00

Orange 134.00

Add $7 50 Shipping and Handling tor this item.

Features:

• Composite Video InputlOutput

• Switchable Input Impedance 75 or
10K ohm

• 750 Line Resolution at Center and
500 Lines at Corners

• Dimensions are 12.13"»11.34"«
11.65" for the 12" model and 8.66"
"8.54"x9.05" tor the 9" model

164

16K RAM MODULE (MX-1BKP) 49.95
64K RAM MODULE (MX-B4KP) 119.00

> Built 4n output connector for piggyback

'Lip for mounting on ZX-81 & KD-81

• High impact plastic case with vaporized metal shielding

>6.6" wide, 3.2" high, 1.08" deep

jtS=- SUNTRONICS
== CO., INC.

12621 Crenshaw Blvd.
Hawthorne, CA 90250

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STORE HOURS: MON.-FRI.
SATURDAY

CALIFORNIA OUTSIDE CALIFORNIA TOLL FREE

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Ifor Tech Into and Calif orders' lOrder Desk Only

Mail Order - Minimum Order $10. Send Money Order
or Check to P.O. BOX 1957 - HAWTHORNE, CA
90250. VISA or Mastercard (please include expiration

9:00 am to 6:30 pm date). Add $4.00 postage and handling to order.

10:00 am to 5:00 pm CA residents add 6% sales tax.

CIRCLE 66 ON READER SERVICE CARD

Listing of applications, software, addon
hardware, books, catalogs, and maga-
zines. Listing includes author, program
description, types of media available,
minimum equipment configuration, price
and ordering information. Listings by cat-
egory from worldwide sources. Over 600
listings from over 160 suppliers.

Oxford Computer Publishing Ltd.

Machine Code Test Tool ZX81 & Timex

lOOO

16K RAM. Cassette: $19.95.

The ultimate tutor and debug pro-
gram. Lists and displays machine code
instructions as they are written. Ideal for
both the novice and the expert.

Prentice-Hall, Inc.

Programming Your Timex/ Sinclair 1000.
By Michael & Simon Barnett. $12.95.

Shows families how to utilize the
TS1000 in the home. Everything from
doing homework to household manage-
ment.

Programming Your Timex/ Sinclair 1000
in Basic.

By Mario Eisenbacher. $9.95 (paper);
$17.95 (cloth).

Introduction to Basic programming for
those with no previous computer experi-
ence. Easy to digest format leads the user
through hands-on examples of programs
in the early chapters and helps develop
skills gradually for more complex pro-
grams.

Programs for Your Timex/ Sinclair 1000.
By Melbourne House Publishers. $9.95
(paper); $15.95 (cloth).

Fully explained programs, scores of
programming hints and space saving tech-
niques, and PEEK and POKE expla-
nations. 30 varied programs including
Blackjack, Checkers, Battleship, Craps,
Simon, Breakout, Mini adventure, Roul-
ette, Starwars.

30 Games for the Timex/ Sinclair Com-
puter.
By William Behrendt. $4.95.

30 games ranging from fortune telling
programs to simulation of the ecosystem.
Fun and engaging.

Timex /Sinclair Interfacing: Tested Pro-
jects for the ZX80. ZX81, and the
Timex/ Sinclair 1000.
By James Downey. $10.95.

How to construct interfaces with in-
structions for building a relay controller,
a joystick interface, analog to digital con-
version and more.

Que Corporation

Timex/ Sinclair 1000 User's Guide. Vol. 1
By Joseph C. Giarratano. $12.95. $9.95.
A practical guide for learning to pro-
September/October 1983 e SYNC

gram. Introduction to computers, how to
use it as a simple calculator, then as a
super calculator, then as a computer to
run programs. Learn how to use pre-
recorded programs and how to write your
own through chapters on Basic program-
ming, utility commands, input, tests and
decisions, loops. 228 pp.

Reddltch Electronics

Programming For Real Applications
16K RAM. £6.95 plus s&h.

Includes programs for personal finance,
word processor, bulk storage, money,
banking, educational, hardware improve-
ments. Cassette tape also available
(£11.44).

Reston Publishing Co.

Basics of limex Sinclair WUU, Z.X81

Basic.

By Allen H. Wolach. $10.95.

Covers hierarchy of arithmetic opera-
tions; entering programs; branching;
arrays; loops; multidimensional arrays;
simulating library functions; using sub-
routines; SLOW and FAST mode; re-
lational operators in logical decisions;
plotting; graphics in strings; plotting;
slicing; strings in arrays.

The Explorer's Guide to the ZX81 and
Timex Sinclair 1000
By Mike Lord. $12.95.

The classic "advanced" book for the
TS1000 and ZX81, now available in the
U.S. and Canada. New features of Basic;
new machine code programming tips
and elements of the ROM; 30 games and
other programs: application routines;
hardware tips; how to add a fullstroke
keyboard; and more.

Fifty 1K/2K Games for the ZX81 and
Timex Sinclair 1000
By Alastair Gourlay, James Walsh, and
Paul Holmes. $10.95.

A new selection of games designed for
the TS1000 and ZX81; all in 1-2K. Fea-
tures such arcade favorites as: Dogfight,
Breakout, Outlaw, Galaxian, Roadracer,
Alien Invasion, and dozens more.

Self-Teaching Software for the ZX81 and
Timex /Sinclair 1000
16K RAM. $29.95 each.

Children from grades 1-6 will find ba-
sic arithmetic skill instruction and nu-
merous practice programs. Each
package contains 2 cassettes with 32 les-
sons, games and activities, and an
explanatory booklet. A classroom aid.
Packaged in a durable vinyl binder. Six
units each sold separately. By Joseph R.
Gladstone.

Making the Most of Your ZX81
By Tim Hartnell. $10.95.

September/October 1 983 « SYNC

This handbook focuses on the addi-
tional features of the TS1000 and ZX81.
New games and useful learning tricks
help show how to write programs that
really work! It will guide users from
start to finish, through each feature and
function of the TS1000/ZX81 personal
computer.

Mastering Machine Code on Your ZX81.
By Toni Baker. $12.95.

Using this guide, the reader learns the
ins and outs of ZX machine code

translation. The handbook reveals the
secrets of the ZX8 1 and shows how to
adapt the ZX81 code to the ZX80
machine.

49 Explosive Games for the ZX81
Edited by Tim Hartnell. $10.95.

Galactic Intruders, Checkers, Death
Maze, Breakout, Smuggler's Mold, and
44 other favorites, newly adapted for
your TS1000 or ZX81. Contains com-
plete programming instructions, plus
easy-to-understand game rules.

THE mlllDUIRRE UNE OF SOFTWARE
FOR TIMEX/SINCLAIR COMPUTERS

GULP

LABYRINTH

tioDDle vou!

*avtr>rougn

maws crtasea tnrougri

ov ogres 3 Ococfloi

St SIS

Can yOutind
youi way

:i595

H10T

Cockpit
controls
teat teacn you
no* to
navigate
J1995

GftAPHIC GOLF CROSSWORD ANAGRAMS WORD TfST

A challenging

iB-noie
goit course
19 95

Create and piay Try lo put the
your own scrambled

crosswords words

$1595

(If Jl

All kinds ot
question and
■ ■
S1S9S

MUiTirif
CHOICE

Can you pick
the correct
answer''
S1S9S

Hyperspace
laser turtles
among the
stars'
$tS95

FAST LOADING Mmdware's proprietary
Quickload * feature lets you load
programs up to (our times faster
than conventional Timex/Sinclair
programs Quickload software also
alerts you to misioads, and lets you
restart the tape from the point of
interruption, without re-loading from
the begming

• QUALITY TITLES Mmdware software is
written by top British software
developers, including Picturesque.
Hewson, Hiiderbay. Asher. Campbell.
Axis. Jones, Vortex and Silversoft

i USER-ffllEKOlY Documentation provides
clear instructions, learning examples,
and trouble-shooting tips.
(All programs require 16K.(

I
I

THE ONLY PLAIN PAPER. DOT-MATRIX I

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CIRCLE 27 ON READER SERVICE CARD

The ZX81 Pocket Book
By Trevor Toms. $10.95

Helps readers create their own pro-
grams and understand why they work. It
shows what the ZX81 or TS 1000 can do,
and how "extras" can help it do more.
Reveals new applications for ZX81 Ba-
sic; offers simplified data file storage and
retrieval techniques and more.

Softest

M Code, Basic Booklets $20.

Rapid Reference Series 8 page booklets
on machine code and Basic. Instruction
set is collated and set out for ease of
access. Similar to a comprehensive set of
prompt cards.

Sybex

More Uses for Your Timex Sinclair 1000:
Astronomy on Your Computer
By Eric Burgess. $6.95.

Look at the stars in your own personal
planetarium with programs that allow you
to observe the apparent movement of the
stars, planets, and meteor showers. Writ-
ten in Basic and ready to be entered on
your TS 1000. 176 pp.

Your Timex Sinclair 1000 and ZX81
By Douglas Hergert. $6.95.
176 pp. ISBN: 0-89588-099-7.

Discusses the setup, operation, and
capabilities of the computer; how to con-
nect it to a TV; benefits of additional
attachments; how to program for a variety
of tasks, e.g., doing calculations, making
bar graphs, drawing pictures on the
screen, playing games.

Timex Sinclair 1000 Basic Programs in

Minutes

By Stanley R. Trost. $6.95.

Collection of useful programs to take
full advantage of each of the TS1000
function capabilities. Calculate home
finances, analyze business and personal
investments, investigate real estate
options, analyze data, keep records.
Ready-to-run programs. No knowledge of
Basic is required. Just ENTER the pro-
grams and you are ready to compute.

The Timex Sinclair 1000 Basic Hand-
book
By Douglas Hergert. $4.95.

Describes and provides examples of
each word in the TS1000 Basic vocabu-
lary. Every keyword and function is
explained carefully and thoroughly. Short
example programs illustrate the use of
each command in its syntactically correct
form. Special notes provide insight to
subtleties and extra features of each Basic
word. 170 pp.

Your Timex Sinclair 1000 and ZX81
By Douglas Hergert. $6.95.

Answers your questions about the set
up, operation, and capabilities of your
computer: how to connect it to your TV
set, the benefits of additional attachments,
how to program it for a variety of tasks
such as doing calculations, making bar
graphs, drawing pictures, playing games.

Tab Books Inc.

A Kid's Manual for Programming the
Sinclair/ Timex Computers. $6.95 (paper)
(FPT $7.25); $12.95 (hard).

Written by an elementary school teach-
er with experience in classroom use of
computers. Makes programming exciting
for any age group. A fun alternative to
plug-in games that helps to prepare
today's kids for the computer dominated
environment they will face.

Using & Programming the ZX81/TS1000.
including Ready to Run Programs. $7.95
(paper) (FPT $8.25); $14.95 (hard).

Everything the beginner needs to learn
and how to put it to work in a variety of
applications. Introduction to the essential
concepts of hardware and software, the
unique characteristics of the TS/ZX ma-
chines and a mini-course in Basic pro-
gramming.

TSG Enterprises

The Watchmakers Guidebook to the
Timex Sinclair Computers. $4.95 pp.

A directory of suppliers with a brief
description of their wares including about
250 software, 100 hardware, 30 ancillary.
Directories of user groups, Timex/Sinclair
specific magazines, newsletters, direc-
tories, books, and articles in other maga-
zines, An introductory chapter about
writing a program in Basic.

V and H Computer Services

What can I do with IK?
By Roger Valentine. £4.95.

40 programs and routines for the unex-
panded ZX81 or TS1000. United King-
dom publication; also published in US by
John Wiley Inc.)

What can I do with 16K?
By Roger Valentine. £4.95.

11 fully documented programs for the
16K RAM ZX81 orTSlOOO. United King-
dom publication; also published in US by
John Wiley Inc.

What Can I do with My Timex Sinclair

1000? Lots!

By Roger Valentine

$9.95; $19.95 w/cassette.

56 programs for the TS1000, incl. 35
that run on 1 or 2K, presented with

clear descriptions that teach program-
ming principles by example. Includes
sophisticated games, file programs,
graphics, personal finance. Also avail-
able on optional cassette.

John Wiley & Sons

Byteing Deeper into your Timex Sinclair

1000

By Mark Harrison. $12.95.

A step-by-step guide to the capabili-
ties and limitations of the
TS1000/ZX81. Teaches TS1000 Basic
programming, and includes 37 programs
of increasing complexity as examples.
Programs for games, math, graphs &
graphics.

Timex Sinclair 1000 Basic: Quick Ref-
erence Guide
By Held. $2.95.

A reference card to the TS1000 key-
board, commands, functions, statements,
symbols, and messages, designed to be
kept right with the computer for instant
access.

TS2000/Spectrum
Books

The books in this section apply to the
TS2000 series. We have listed only those
supplied by U.S. publishers here. See Eric
Deeson's "The Bookshelf Goes
Supernova" elsewhere in this issue for a
collection of publishers and titles in the
U.K.

Birkhauser Boston, Inc.

Introducing the Timex/Sinclair 2000:
Programs, Games, and Graphics.
by Ian Stewart and Robin Jones.
Look for it in fall 1983.

Microscene

Guide to ZX Spectrum Resources
Edited by Eric Deeson. $6.50 (incl air-
mail)

Resource collection includes listings of:
Spectrum suppliers, books, magazines,
user groups, extra memory, add-ons, soft-
ware, and other supplies. Software section
categorized and products are rated in 8
areas on a 6 point scale. 92 pp.

Prentice-Hall, Inc.

Introducing Timex/Sinclair 2000 Machine

Code.

By Ian Sinclair. $12.95.

Enables users to achieve high speed
graphics and advanced game applications
on the TS2000. Available in Sept.

Programming the Timex/Sinclair 2000.
By S. M. Gee. $19.95.
Covers everything from elementary

September/October 1983 «> SYNC

NOW! A COMPLETE LIBRARY OF

QUALITY SOFTWARE FOR THE SPECIAL

INTRODUCTORY PRICE OF $19.95

SIMPLEX SOFTWARE INTRODUCES

THE HOME-PAC - 20 PROGRAMS ON

TWO CASSETTES FOR THE 16K TiMEX

SINCLAIR 1000, 1500 AND ZX81.

Now for under $20, you can get a complete
collection of 20 quality, reliable and user-friendly
programs on two cassette tapes. Although easy
enough for beginners to use, even computer ex-
perts will find these programs usefui. in fact, as
useful as other program packages costing
several times more.

WE FEEL THAT THE HOME-PAC AT $19.95,

WHIQN RETAILS REGULARLY FOR $29 95,

' IS THE BE^St'sOFTWARE VALUE*

IN AMERICA.

Discover the Power of Your
Timex Sinclair Computer!

We've developed the programs that you want
and need. Useful programs to assist you in
home budgeting, education and many other
tasks. We've also included recreational and utili-
ty programs to help you unlock and explore the
power of your computer.

The HOME-PAC Contains
All the Following:

1 . BIORHYTHMS— Computes and plots four weeks
of your biorhythms

2. ANIMALS— Popular artificial intelligence learning game

3. COMPU-SKETCH- Computerized version of popular
ETCH-A-SKETCH toy

4. MICRO-ORGAN— 4 octave organ music through your TV

5 KALEIDOSCREEN— TV screen becomes a computerized
kaleidoscope

6 ADDITION DRILLS - 4 skill levels and scoreboard

7 SUBTRACTION DRILLS— 4 skill levels and scoreboard

8. MULTIPLICATION DRILLS- 4 skill levels and scoreboard

9. DIVISION DRILLS- 4 skill levels and scoreboard

10 COMPUTER AIDED INSTRUCTION- General purpose
education program

1 1 STATISTICS— Computes mean, variance and standard
deviation

12 LINEAR REGRESSION- Computes regression
coefficients and displays equation
VECTOR MATH— Adds two vectors and provides
resultant vector

SIMULTANEOUS EQUATION SOLVER- Solves system
of simultaneous equations

CHECKBOOK BALANCER- Reconciles check register
with bank statement

NET PRESENT VALUES— Computes net present value
of cash flows

1 7 AUTO LOAN ANALYSIS- Computes amount of loan and

monthly payments

STAR INVADER— Mini space invader game

MACHINE LANGUAGE MONITOR- Utility program

enters and lists hex code

RENUMBER— Utility program, renumbers BASIC

programs
21 21 PAGE USER'S MANUAL

18
19

ADDITIONAL SIMPLEX SOFTWARE PACKAGES

REC-PAC: BIORHYTHMS & ANIMALS- Regularly $1 1 .95,

now only $9.95
ART-PAC: COMP-U-SKETCH, MICRO ORGAN &

KALEIDOSCOPE— Regularly $1 1 .95, now only $9.95
EDU-PAC: 4 MATH DRILLS & COMPUTER-AIDED

INSTRUCTION- Regularly $1 1 .95. now only $9.95
MATHSTAT-PAC: STATISTICS, LINEAR REGRESSION,

VECTOR MATH & SIMULTANEOUS EQUATION

SOLVER— Rennlarlv $1 1 95, now only $9.95
FIN-PAC: CHECKBOOK BALANCER, NET PRESENT

VALUES & AUTO LOAN ANALYSIS- Regularly $1 1 95

now only $9.95
COMBO: Computerized variation of popular BOGGLE hidden

word game with 4x5 game board (2 to 8 players) —

Regularly $1 1 .95, now only $9.95

GUARANTEED

All programs are supplied on quality cassette tapes which

are guaranteed to load and run (defective software

will be replaced if returned within 30 days).

ACT NOW! OFFER GOOD FOR LIMITED TIME ONLY!

SEND TO:

SIMPLEX

SOFTWARE

55 Sutter Street
Suite 623 Dept. A-5

San Francisco. CA 94104

PLEASE RUSH MY ORDER

Please send dealer information
Check VISA Master Charge

Address .

HOMEPac 19 95

GTY

TOTAL

RECPac 9 95

ART-Pac 9 95

EDU-Pac 9 95

MathStu-Pac 9 95

FIN Pac 9 95

COMBO 9 95

■

] J 50

$1 50

Calit res add 6 5°o
sates [ax

State_

Zip_

TOTAL

CIRCLE 57 ON READER SERVICE CARD

programming techniques to sophisticated
graphics and sound capabilities. Includes
many listings and game applications.

The Timex/ Sinclair 2000 and How to Get

the Most from It.

By Ian Sinclair. $9.95.

Introduces the TS color computer,
covers machine set up and operation, plus
Basic programming.

The ZX Spectrum: Your Personal

Computer.

By Ian McLean. $12.95.

An introduction to the TS2000 and
Spectrum, explaining the fundamentals
of Basic programming.

General Books

The computer section of any bookstore
these days contains an overwhelming
selection of material. We have gathered a
few titles we have come across which
might be of general interest.

CompuSof t Publishing, Inc.

The Basic Handbook: An Encyclopedia
of the Basic Computer Language. 2nd ed.
By David A. Lien. $19.95.

ISBN 0:932760-05-8

An encyclopedia of nearly 500 Basic
words. Covers the dialects used by over
250 computers manufactured world-wide.
Features special sections on Disk Basic,
TRS-80 Extended Color Basic, Atari
Basic, Tektronix Basic, and converting
programs from one computer to another.
Listed alphabetically with test programs,
sample runs, variations in usage, and al-
ternate spellings. 480 pp., 7x9. Paper-
back.

Computer and Electronic
Supply Services

Computer Guide 1983.

Ed. by S. I. Barrett and L. A. Sweeney.

$37.25.

Guide to over 250 small and personal
computers from over 100 computer com-
panies in 5 sections: application programs
and system software; programming lan-
guages; machine characteristics; con-
sumer information; stores and vendors.
Comparison charts. New editions
annually; quarterly updates. Over 1500
pp.

Dell Publishing Co.

The Official Computer Hater's

Handbook.

By D. J. Arneson. $3.95.

Everything the computer hater needs
to know about: how to destroy a com-
puter; what to do with a dead computer;
how to tell if your teenager is using com-
puters; how to understand computer-
speak; how to turn off computer conver-
sations at cocktail parties; and more. 192
pp.

Wayne Green Books

Inside Your Computer.
By I. R. Sinclair. $12.97.

Explains microprocessor chips, hard-
ware circuits, the interpreter, the use of
machine language; hardware, software,
computer components, the microproces-
sor, the accumulator, and operating sys-
tems. Sections on compilers, assemblers,
monitors, binary numbers, analyzing a
Basic line, and using Basic and machine
code in combination.

Para Publishing

Word Processors &

Processing.

By Dan Poynter. $11.95 pp.

Discusses what word processing is and
how it can help the reader; the parts,
functions, and features of the word pro-
cessor; how to buy one and how much;
sources of additional information; glos-
sary of word processing terms. 172 pp.

$E95

TS 1000-/ZX8V OWNERS:

"TOUCH TYPE" FOR JUST

• Improve programming and game playing, too!

• Easy to install - no wiring or soldering required

• Clear Vinyl with key-shaped openings and
adhesive backing.

TYPEX/81™ Keyboard
$5.95 + $1.50 P&H

Order by mail or phone.

216/234-2662 • VISA & MASTERCARD welcome.
GANHART/EARTHings

115 N. Rocky River Dr. dealer /DI str IB utor

Berea, OH 44017

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INQUIRIES INVITED

CIRCLE 32 ON READER SERVICE CARD

64K INSIDE!!

ZX81

No wobbles!
No bulky add-ons!
No fear of crashing if bumped!
Leaves rear connector free
for preripherals !

The 64KT or 64KZ will increase the
memory INSIDE your computer to it's
full capability of 64K bytes
(including 8k-16k).

It installs INSIDE your computer in a minute
with easy instructions and NO soldering, it
simply plugs into the microprocessor socket.
Or if you prefer, get the memory you want in
a complete kit that you can put together.

The 64KT = TS1000 with ser.
The 64KZ = TS1000 with ser.

no. prefix F or P
no. T or D or ZX81

64KT or 64KZ 110.00

64KTK or 64KZK (kit) 90.00

To order, send the part number you need, and
check or money order (add 4.00 for shipping
and handling) to:

INDEPENDENCE RESEARCH

P.O. BOX 1497

OREM, UTAH 84057

CIRCLE 36 ON READER SERVICE CARD

September/October 1 983 ® SYNC

PC Clearinghouse, Inc.

PC Clearinghouse Software Directory.
$29.95 plus $2.50 s&h.

Comprehensive software buyer's guide
listing over 21 ,000 software packages from
over 2900 software publishers and 200
microcomputer manufacturers. Cross ref-
erenced to hardware, operating systems,
application packages, programming lan-
guages, and prices. 840 pp.

Prentice-Hall, Inc.

The Computer Cookbook: How to Create

Small Computer Systems That Work for

You.

By William Bates. $12.95 (paper); $21.95

(cloth).

Comprehensive reference guide on put-
ting together microcomputer systems
from various component; explains the
ingredients that must be integrated into
finished systems; offers specific, factual,
timely information including an industry
listing.

St. Martin's Press

The Complete Handbook of Personal

Computer Communications: Everything

You Need to Know to Go Online with the

World.

By Alfred Glossbrenner. $14.95.

Shows how to send electonic letters,
telexes; to buy modems and communi-
cations software; using the Source,
CompuServe DJN/R; troubleshooting;
electronic banking; online fact finding;
shopping online; free computer bulletin
boards; free software; encyclopedic data
bases. 325 pp.

Sybex, Inc.

Programming the Z80. 3rd ed.
By Rodney Zaks. $16.95.
ISBN 0-89588-069-5

Covers all aspects of programming the
Z80 in assembly language. Includes syste-
matic descriptions of Z80 hardware orga-
nization, complete instruction set, Z80
addressing modes, data structures. Appli-
cation examples and exercises. 624 pp.

Z80 Applications.

By James W. Coffron. $14.95.

Learn the necessary programming and
interfacing techniques to connect the Z80
microprocessor to common microcom-
puter parts; basic and advanced I/O tech-
niques; diagrams; examples. 288 pp.

Yes! Bookshop

Computers: A Comprehensive Guide.
By Chris Popenoe. $2.00.

A comprehensive guide to computer
books. 819 titles listed and classified:
computer fundamentals; computer and
society; microcomputers (by machine);
languages (by type); assembly languages
and microprocessors; operating systems.
Authors index. 60 pp. 8 1/2 x 1 1. *m

September/October 1 983 « SYNC

BACK-UP

COPIES OF

ANY PROGRAM

FOR16KTS1000/ZX81
MACHINE CODE LOADING
ROUTINE WILL STOP ANY
PROGRAM AFTER LOADING
ENABLING THE USE OF
THE SAVE COMMAND

LISTING $4.00

KATT'S
COMPUTERS

BOX 162 DEPT. T

CHICAGO HEIGHTS. ILLINOIS

60411

BATTERY
BACK-UP

Uninterruptable power supply
for ZX80, ZX81, and T/S1000.
No memory loss when AC fails.
Allows portable computing
7 hrs normal, 4Vi hrs with 16K.
Completely rechargeable with
your computer power pack.

• No wiring, simple plug-ins.

• Safe^easy to uo o , o co fromrcah-

• Ask for WITW ATT 1000.

$36.50 plus $3.50 shipping/
handling, CA residents add 6%
sales tax. Send money order or
check to: WT ASSOCIATES,
3808 Rosecrans St., #262, San
Diego, CA 92110.

DON T RETURN
TO
COLLEGE!

WITHOUT TAV1N:- Mut'SY KITH YOL'
HOPSY (Matrix Operations Programming Systi
a computer program for college students, profes-
sionals and scientists, developed for use in
personal computers.

MOPSY performs Standard Matrix Operations: adds,
svibt rar-r s , multiplies, transposes, inverts, cal-
culates determinants, scalar multiplies and
stacks matrices, in addition, of course to I/O
and editing.

A non standard ooeratior, is also provided, for
the solution Of edvar
non linear problems.

You get cassette with program recorded tvict .
User's Manual describing options and Application
Manual describing solution of linear simultane-
ous equations, polynomial interpolations, best
fit of curves with linear regression as a parti-
cular case, advanced statistics, numerical inte-
gration, electric circuit analysis, truss, analy-
sis, hydraulic network analysis, animal popula-
tion and harvesting studies and more.

To order, specify computer (T1MEX-SINCLMR 16K
or COMMODORE 641, send $25 Check or M.O. to
MOPS)
P.O. Box 196
Glen Oaks, N.Y. 11004
N.Y. reisdents add B.25 * sales tax.

SyncMaster

has the programs for your Timex-
Sinclain precision-designed and tested,
thoroughly documented, guaranteed to
perform to specifications.

CONSUMERS —

if you don't see what you need here,
write us: DEPT. WHAT-I-WANT, and
tell us what you need or want. We
will rln ni.ir best to deliver.

*— . *— "T

1 SCREEN MACHINE S1495

. Place input prompts anywhere on screen wjere

SS S shows max.mum length ot each Input
2. MNEMOSYNE ASSEMBLER S19.95
by Nathan Finstein

. Two taoes with proven Source Editor fast I loader
i650-baud) and lull-featured assembler • JU pius
™p manual • HAM size set automatically. 6 to
S 9 K Tst to screen and/or printer • Editor tunc
ns add. move, change delete. ,,nd s ring, ind
tan scroll block move block • Fast loaoei u j
tones Mer than Sinclair) can be used in your own
Pragrams • Menu dnven. rapid program develop-
ment cycle
3 GRADE BOOK $ 14 ■•§

•jSswsWgSsi?

m -in raades oe' studenl • Unlimited classes
SSSS^e^KSn
data entry and editing

4 FINANCIAL ANALYZER S14.95
7'sa Hg SSS on Prepaying mortgage princ^a
. What well your IRA be worth in the year OTJ
. What «s y the real yield «V"? '"jS™^
. Simplify all standard interest rate calculations
. tw2 screens lull ot calculations to he p you inv
wove your financial position* Uses screen
Machine tor full screen data entry and editing

Som data mean, standard deviation, mm/max
' co Sons co-vanances. linear regressions, chi-

fauae hypothesis tests, two way cross tabuta-

wHI ! two-dimensional frequency dab

fi INSURANCE RECORDS S14.95

. t n piete "ecord keeping of household, business

Ss^:ecS«^«

and editing

7 VU-WRITE TEXT EDITOR S14.95

characters in t6K

• All prices plus S1 for postage

• All cassettes high-quality,

guaranteed to load

$2 tor any manual
payment credi

^0t^,^m i * ii. * m \

mial plus catalog; I
ited to first order \

DEALER INQUIRIES INVITED

Great margins available.

SyncMaster

919/643-7120
P.O. Box 511, Oak Ridge. N.CJ!7310

We're looking for programs in all fields. We
will publish your programs, paying top
royalties to you. it your programs are the best
in their field and truly useful

CIRCLE 69 ON READER SERVICE CARD

The Bookshelf Goes Supernova Eric Deeson

Maybe old-stagers among the SYNC
readership will recognize the allusion in
my title. It refers to a piece of mine
published here in the March/April 1982
issue. Called "The Exploding Bookshelf."
the feature listed some 40 books on the
ZX81 available in Britain at the end of
the machine's first year of existence.

Now. a year and a half after that piece.
I must tell you I have lost count of ZX81
titles. I would not be at all surprised if the
length of the list has doubled by now—
there is no doubt that the ZX81 is here to
stay. Well, for a few years yet.

However. I am now to survey another
shelf in the bookcase, that containing the
books on ZX81"s younger sibling, the
Spectrum. It is now somewhat more than
a year since that machine first appeared
and, again, the number of books on it is
of the order of forty. Before looking at
these publications in any detail. I would
like to make a few observations.

Observations

1) The books are bulkier now. Many in
the ZX81 list had below a hundred pages:
hardly any of the Spectrum books are so
small.

2) The books are more professional
now. Sir Clive Sinclair has created more
than a trio of micros, and around them
have grown hundreds of companies, many
of which are frighteningly well-off. Sin-
clair converted some tiny publishing
houses into comparative giants and
caused the actual creation of others
whose sales go into hundreds of thous-
ands. The new wave of books are glossy,
illustrated with photos and clear listings,
and properly proof-read. Yet the price-

Eric Deeson. 4 Ethel Rd.. Harbonnc. Birminsham
B17 0EL.

■ he Spectrum books are bulkier, more
professional, glossy with photos and clear
listings, and proofread, yet cost no more.

range has hardly changed, being still £2.50
to £10 ($4.00 to $16.00).

3) Existing publishers have made little
impact yet on this market. Their main
problem is that they are used to years
between commissioning and issuing. The
new companies can get a manuscript into
the bookshops in weeks. Maybe the big
publishers will have to save face with a
potentially successful drive into software.

The List of Books

In this survey I shall follow the pattern
of "The Exploding Bookshelf." First
comes a list, in publisher order, of all the
books I know of. My brief comments
follow the book listing; if there are none,
it is because I have not seen the book.

Two extra details appear in the list this
time. First is the UK price, where known.
This is given because I used up SYNCs
fee last time in replying to your queries
about prices. Some books are available in
North America, and you will have to
research that.

However, you can order direct from
Britain. I trust no publishers will complain
if you send them payments worked out
like this. To the quoted price add £1.50
for airmail postage, etc. (£2.00 if the book
costs more than £5.50). Remit that
amount as a sterling cheque; if you wish
to pay in dollars add another £1 before
converting because British banks charge
outrageously for dealing in dollars!

In case of doubt about prices and ship-

ping costs, contact the publisher directly.
Or you can contact a major distributor if
you want several books. I recommend
these two:

Software Bookshop, 30 Lincoln Road,
Solihull, West Midlands. UK.

Mine of Information, 1 Francis Ave.,
St Albans, Hertfordshire, UK.

The second extra data item in the pre-
liminary book listing is a code for type of
book. I have identified five classes:

B: Beginner"s introduction; attempts to
put the (excellent) Manual into more suit-
able terms for novices.

P: Program collection; material which
does not do more than give superficial
notes on listings.

I: Intermediate coverage; more in
depth work for those with some knowl-
edge of Sinclair programming; may get
into machine code somewhat.

A: Advanced work; for people who
have mastered Spectrum Basic (which is
not much different from TS1000 Basic).

M: Miscellaneous.

Following the broad shallow listing
comes a list of half a dozen books with a
paragraph or two discussion that I would
recommend as being particularly good
values. That is a personal recommen-
dation, but, well, I do reckon to have
made a deep study of Sinclair resources
in practice. Even so, there may well be
omissions, so I would best apologise now
to any aggrieved publishers wondering
why they have been left out.

September/October 1983 ® SYNC

^ I Good reasons why you should
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Understanding Your Spectrum by Ian Logan is a treasure
trove of hints and tips and useful routines
and details a dozen Spectrum bugs.

The Bird's Eye View

Addison-Weslev, 53 Bedford Square,
London WC1.

M: Logo Challenge, Govier and Neave.
25 pp. £29.95 (incl. workbook and 2 cas-
settes). A superb package for home and
school use on turtle graphics; good, but
cramped, pupil work book: excellent
teacher is guide; and two nicely packed
cassettes. Important.

Altwasser, 22 Foxhollow, Bar Hill, Cam-
bridge 3.

P: Cambridge Colour Collection, Alt-
wasser, 64 pp. £6.95 (cassette available).
The first book on the Spectrum. Fair
enough: Altwasser designed the
Spectrum. 20 good Basic programs with
instructions but no notes.

Armada, Westerhill Road, Bishop-
briggs, Glasgow 64.

B: First Steps with Your Spectrum,
Hughes, 128 pp. (due July). Very well
illustrated introduction for children.

AVC, PO Box 415, Birmingham 17.

P: Learning with the Spectrum, Deeson,
24 pp. £1.50 (cassette available). The
second book(let) on the machine; 10 pro-
grams for school and home learning ob-
jectives: instructions and programming
notes.

Collins Educational, 5 Buckingham
Place, London SW1

M: Spectrum Starter Pack I. McBride.
77 pp. £9.95 (including cassette). An in-
tegral cassette/workbook in fine style
introducing Spectrum programming.

M: Spectrum Starter Pack 2. McBride,
1 12 pp. £9.95 (including cassette). Second
half of the above.

Duckworth, 43 Gloucester Crescent,
London NW1.

I: Spectrum Graphics, Hampshire. 192
pp. £6.95. A hasty non-technical col-
lection of graphics programming tips and
listings.

P: Spectrum Programmes, sic,
(Hampshire).

Gower, Croft Road. Aldershot, Hamp-
shire.

B: Learning to Use the ZX Spectrum,
Bradbeer. 76 pp. £4.95. An amazingly
superficial introduction from a usually
brilliant writer, who indeed co-authored
the Spectrum manual.

Granada, Frogmore. St Albans, Hert-
fordshire.

B: The ZX Spectrum, Sinclair (no-
relation), 130 pp. £5.95. Sometimes su-
perb, sometimes too speedy; overall
good.

P: The Spectrum Book of Games,
James, £6.95.

B: The Spectrum Programmer, James,
£6.95.

Hewson, 60a St Mary's St., Wallingford,
Oxfordshire.

P: 20 Best Programs for the Spectrum,
Hewson, 118 pp. £5.95. A well-varied
collection, generally of high standard,
with often excellent notes. See below.

A: 40 Best Machine Code Routines for
the Spectrum, Hardman and Hewson, 144
pp. £5.95. Nicely laid out and fully ex-
plained; this is not a collection of routines
but a good grounding text with good
examples.

Interface, 44 Earls Court Road, London
W8.

B: Programming Your ZX Spectrum,
Hartnell and Jones, 231 pp. £6.95.
Another of the first few before the flood;
half written by Tim Hartnell, once the
most prolific Sinclair writer [Interface was
set up by him); a very thorough book.

P: 60 Games and Applications for the
Spectrum. Harwood, 90 pp. £4.95. All
kinds of program here, generally short
(which is good); supplied with instruct-
ions.

Linsac, 68 Barker Road, Middles-
borough. Cleveland.

I: The Spectrum Games Companion,
Maunder, £5.95. Not seen, but. if it follows
the pattern of Maunder's earlier serious
ZX books, this will be good value.

Macmillan. Basingstoke. Hampshire.

A: Advanced Graphics with the Spec-
trum. Angell and Jones, 254 pp. £9.95
(cassette available). An absolutely mar-
vellous book for really serious program-
mers. See below.

Melbourne House, Glebe Cottage,
Station Road. Cheddington, Leighton
Buzzard, Bedfordshire.

P: Over the Spectrum, various, 164 pp.
£6.95 (cassettes available). 300 lengthy
programs in good variety; detailed notes;
plenty of illustrations.

A: Understanding Your Spectrum,
Logan, 192 pp. £7.95. Tough going but
super. See below.

A: Spectrum Machine Language for the
Absolute Beginner, Tang, 245 pp. £6.95.
Very thorough but rather dry.

M: The Complete Spectrum ROM Dis-
assembly, Logan and O'Hara, 236 pp.
£9.95. For the real specialsist a true gold-
mine: a superb volume is this.

M: Spectrum Hardware Manual,
Dickens, 108 pp. £5.95. How the thing
actually works; some nice tweaking ideas:
very thorough.

Microscene, Battenhall Road, Har-
borne, Birmingham.

M: Guide to ZX Spectrum Resources,
Deeson, 92 pp. £2.00. Details of over 200
suppliers to this market and their pro-
ducts; illustrations; reviews. I think it is
invaluable, but I would, wouldn't I?

Phipps, 99 East Street, Epsom, Surrey.

I: The Spectrum Pocket-book, Toms,
160 pp. £5.50 (cassette available). Useful
programs, lots of tips, and nice intro-
ductions to topics like machine coding.
See below.

Prentice-Hall, 66 Wood Lane End,
Hemel. Hempstead, Hertfordshire.

B: The ZX Spectrum— Your Personal
Computer, McLean et al., 220 pp. £5.95.
Rather too slow-moving, or very careful —
depends on your speed I guess!

Shiva, 4 Church Lane, Nantwich,
Cheshire.

B: Easy Programming for the Spectrum.
Stewart and Jones, 139 pp. £5.95 (cassette
available). Far and away the best intro-
duction to Spectrum programming. See
below.

P: Computer Puzzles for Spectrum.
Stewart and Jones, 60 pp., £2.50. A wide
variety of old and new teasers; good in-
struction; very well illustrated.

P: Games to Play on Your Spectrum.
Wren-Hilton. £1.95. A very pleasant little
book; just right for the transition between
purchased games and your own.

I: Further Programming for the
Spectrum, Stewart and Jones. 162 pp.,
£5.95. Another brilliant book from Stw-
art and Jones which I would deal with in
depth below except I already have two of
their magic spell-binders in that section.

I: Spectrum Machine Code, Stewart
and Jones. 103 pp., £5.95. Anyone else's
treatment of this topic would be coded A.
Say no more? Well, I do say more! See
below.

M: Spectrum in Education, Deeson, 176
pp., £6.50. So far the only coverage of
Spectrum usage in a specific applications
area; this looks at many kinds of appli-
cations in classroom and home learning
situations; 50 programs, too. If I were not
so scared of the author I would put "see
below" now, but I wouldnt dare do that.

Sigma Technical, 5 Alton Rd., Wilm-
slow, Cheshire.

B: The Sinclair Spectrum in Focus,
Harrison, 190 pp., £6. 25. A thorough and
thoroughly nice introduction that verges
on I category in range of content.

Sinclair-Browne {the Sinclair), 10 Arch-
way Close, London N19.

I: The ZX Spectrum Explored. Hart-
nell. 218 pp., £5.95. A unique attempt at
providing a serious overview of the Spec-
September/October 1983 e SYNC

TIMEX and SINCLAIR FORGOT!
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CIRCLE 23 ON READER SERVICE CARD

STOP PLAYING GAME

■ Calculate odds on HORSE RACES with ANY C0MPU-

sing BASIC.

■ SCIENTIFICALLY DERIVED SYSTEM really works TV
Station WLKY ot Louisville Kentucky used Itus sytem
to predict the odds ot the 1980 Kentucky Derby See
the Wall Street Journal (June 6 1980) article on
Horse-Handicapping This system was written and
used by computer experts and is now being made available to home computer owners This
method is based on storing data from a large number ot races on a high speed large scale
computer 23 factors taken Irom the Daily Racing Form were then analyzed by the
computer to see how they influenced race results From these 23 factors ten were found to
be the most viral in determining winners NUMERICAL PROBABILITIES ol each of these 10
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4 1 Tips on using the odds generated Dy Ihe program

5) Sample form to simplify entering data lor each race
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- Full documentation to get the most from your ZX81

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PROGRAMMERS TOOLKIT and GRAPHICS HUU I iNtS

CARTRIDGE $29.95

A 16K to 64Kcompatible cartridge that plugs into the back of the ZX/TS. It
provides 8 programming aids such as: RENUMBER, DELETE. REMGEN,
etc and 15 graphics aids that will ROLL or SCROLL the screen in any
direction. DRAW or UNDRAW a predefined figure anywhere on the
screen, BACKGROUND, and more. Allows use of all 24 lines of the screen.
EPROM on cartridge uses the 12K to 16K block of memory so that none of
the BASIC programming area is used (add $2 P&H)

PROGRAMMERS TOOLKIT and GRAPHICS ROUTINES on cas-
sette $995

Same as cartridge version except requires RAM in 12K- 16K area.

DRY GULCH on cassette ( 1 6K) $9.95

An interactive adventure where the user types in short English phrases
such as: Go North, Take the Hammer, Saw the Iron Bars etc to explore an
old west ghost town in search of treasure Written in BASIC and SAVEable in
progress Estimated time to solve is 10-12 hours. Try this adventure first.

MORLOC CASTLE on cassette (16K) $14.95

Similar in style to DRY GULCH. MORLOC CASTLE is, however written in
machine language to provide much faster response Provides over 200
words of vocabulary, is SAVEable in progress and uses every last byte of
RAM. VERY DIFFICULT (hint sheet available) estimated time to solve 30-50
hours.

EPROM CARTRIDGE KIT $17.95

A complete kit (less EPROM) to build a plug in cartridge that will accept
one 2716, 2732. or 2764 EPROM Board may be memory mapped in 4Kor
8K increments in 8K- 1 6K area of memory ( 1 6K-32K if RAMpack is not used).
(Add $2 P&H)

EPROM PROGRAMMER KIT* $39.95

A complete kit to build a programmer for 2716. 2732. 2732A and 2764
EPROMS. Includes. PC board, all parts (except 28v or more power supply).
cassette, and instructions. (Add $2 P&H)

EPROM PROGRAMMER ASSEMBLED* $49.95

As above except assembled and tested (Add $3 P&H)

I/O PORTS AND EPROM PROGRAMMER PLANS $5.00

Schematic documentation and software listing to build a 24 line I/O port
then use it to program 27 16, 2732, 2732A or 2764 EPROMS. Bare PC board
available for S1 7.95.

'NOTE: compatible only with feedthrough type RAMpacks like MEMO-
TECH. BYTE BACK etc NOT compatible with TIMEX or SINCLAIR RAM-
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CIRCLE 64 ON READER SERVICE CARD

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I he best introduction for beginners to computing
is Easy programming for the ZX Spectrum.

trum and its uses; a mishmash of pro-
gramming material, games, and text (il-
lustrated with more listings, on business
and education. A mishmash, true, but
actually a well-knitted and readable one.

Sunshine Books, 19 Whitcomb St.,
London WC2.

I: The Working Spectrum, Lawrence,
216 pp., £5.95. Subtitled "A library pf
practical subroutines and programs"; this
is not. It does contain lots of modules,
some quite useful, broken carefully out
of 19 lengthy programs (in many fields),
but you cannot trace them.

Timedata, 16 Hemmells Laindon,
Basildon, Essex.

I: Exploring Spectrum Basic. Lord).
Lots and lots of great little listings with
many new tips and effects; useful appen-
dices, too.

The Worm's Eye View

Now I will turn to a more detailed
consideration of the books I view as the
best half dozen! Of course, those by that
Deeson chappie are really the best but I
shan't mention them again! Can't afford
accusations, after all.

It seems sensible to begin at the novice
end and narrow in to the more specialised
staff.

I have absolutely no doubt that the
best introduction for beginners to com-
puting is Easy Programming for the ZX
Spectrum by Ian Stewart and Robin Jones
(Shiva). Ian is a world-renowned expert
in catastrophe theory, an abstruse branch
of math, but I am sure his bank manager
is more delighted at his ability to turn out
brilliantly readable programming books
with Robin.

This one, accessible to youngsters and
enjoyable by adults, is written in a
gloriously user-friendly style with lots of
good illustrations (even cartoons, another
product of the Stewart brain) and gently
developed program listings.

The book covers Basic throughly des-
pite its fairly short length and uncramped
style, going from square one to graphics,
sound and PEEK/POKE. It is no bind to
work through at any speed, and, when
you reach the end, you will know a lot
about programming (concepts as well as
techniques) and have some super pro-
grams on tape.

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CIRCLE 63 ON READER SERVICE CARD

As I said above, Tim Hartnell, author
with Dilwyn Jones of Programming your
ZX Spectrum (Interface), was right up
front in the early Sinclair years. He started
magazines and a great user group and
wrote and wrote and wrote. He is pretty
well retired now. This book does not show
any of the haste of his original works and
attempts to be definitive and comprehen-
sible as well as "all things to all men" (and
women). There are millions of program
listings, but they do not overshadow the
text, which remains fairly thorough and
well-graded.

Once one has gone through an intro-
duction to Spectrum Basic it is natural to
turn to collections of rather more am-
bitious—and lengthy— listings. Thus one
can learn more and build up a reasonable
software library. The dangers with col-
lections are two-fold: (a) inadequate
proof-reading, and (b) inadequate com-
mentary.

Andrew Hewson's 20 Best Programs
(Hewson Consultants) suffers from nei-
ther fault. Andrew, too, has been well-
respected in the British Sinclair field for a
long time, and that respect arises from his
detailed knowledge and thoughtfulness.
Both attributes are apparent in this book,
surely the best of the P bunch for people
wanting to learn rather than transfer ma-
terial mindlessly from paper to screen.
The 20 programs are fairly lengthy, per-
haps 2-3 sides on average, but they range
particularly widely in usage and are ex-
tremely well backed up in the text. We
miss the way Andrew's earlier books gave
lots of little tips, too, but perhaps we will
be lucky enough to get a whole book of
those sometime. Mike Lord's Exploring
Spectrum Basic (Timedata) was a strong
contender for this spot because it does
contain tips, but it lost out in being com-
paratively disjointed.

Trevor Toms is yet another name you
might know. His books have always been
beautifully presented (even if a bit pedan-
tic, and The Spectrum Pocket-book
(Phipps Associates) is no exception. It
does contain lots of hints (including the
invaluable PAUSE 4E4 from ZX81 days
that the Spectrum replaces with PAUSE
0!). However, Trevor's book mainly con-
sists of programs, all fully annotated and
material on programming philosophy. He
goes a fair way into machine coding, too,
but for the best introduction to that we
must return to Ian Stewart and Robin
Jones for their Spectrum Machine Code
(Shiva). This is identical in style, ap-
proach, and outstanding value to their
Easy Programming. It is not a heavy text
on binary /hex/Z80 this and that; nor is it

September/October 1983 • SYNC

a dreary collection of ill-connected rou-
tines. It is a guide in the real sense of the
word, in which the authors take you
charmingly by the hand and lead you
through machine code thickets in such a
way that you do not notice that they are
thickets at all. Even 10-year olds can
compete in the arcade stakes with this
book!

Among the advanced specialist works.
we come first to Understanding Your
Spectrum by Ian Logan. Ian seems to
have dedicated his life to messing around,
Tron-style, inside Sinclair chips. Subtitled
"Basic and machine coding program-
ming," this particular book is more acces-
sible than some of the others. It is a
treasure trove of hints and tips and useful
routines and details a dozen Spectrum
bugs, some of which of course have now
been splatted.

The Basic material is a minority in
Logan's book: he provides a summary of
the keywords and their uses, briefly but
always with novel points for consider-
ation. The bulk of the volume is not deep
machine code, but a bright and definitive
look at ROM routines you can use in
Basic programs and such like. The pages
still look rather formidable at first sight,
but closer examination will trap you into
a great deal of midnight oil.

Advanced Graphics with the Spectrum

by Ian Angell and Brian Jones (Mac-
millan) (yet another Ian; yet another
Jones) is a quite marvellous book, after
the publication of which no one can ever
again say that the Spectrum is a toy! To

be able to work through it you need good
Basic, thorough math (Grade 12, say),
and much patience. That is because this
field is not a toy one, and the authors do
not leave much out even if they write
always in a user-friendly way.

The book is well illustrated, as it needs
to be in view of its content, and most
adequately proof-read. The program
material consists of many sub-routines
(well-defined modules, which link to-
gether to produce the various systems
required). In this way the authors take us
from character graphics to orthographic-
projection with hidden line removal. The
only area they do not touch is machine-
code graphics, but that would be too
much to ask for.

The ZX81 is alive and well in its home-
land and the number of books on it grows
steadily. All the same, after well over a
year of the excitement of the Spectrum
(an incredibly popular machine), publish-
ing on that is where the action is. My
main list is not complete, remember-
there has probably been a book a week
on the Spectrum since early last summer.

Bookshelf explosions are a real possi-
bility— I now have more computer books
on the floor than on the wall rather than
risk having the wall come down! Far over
a hundred Sinclair-based books do not
help at all. fm

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SIN WARE provides these quality
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STEP

STEP provides line-at-a-time execu-
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Z-TOOLS

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CIRCLE 60 ON READER SERVICE CARD

Book Review

Learning Timex
Sinclair Basic

Sharon Zardetto Aker

Learning Timex Sinclair Basic by David
A. Lien. Compusoft Publishing. $14.95.

If you have ever thrown down your
TS1000 User Manual in despair— or dis-
gust, help has finally arrived: David Liens
Learning Timex Sinclair Basic. It is a
clear, thorough guide to programming the
Timex Sinclair 1000, but ZX81 and ZX80
users are not ignored. No matter how
"learner friendly" the manual for the new
TS1500 will be, it could not be friendlier
than this.

Lien takes the reader from plugging in
the computer and doing a first PRINT
command to writing search and sort rou-
tines and using PEEK and POKE. A sam-
ple program illustrates every new con-
cept, and many of them are revised in the
light of new materials presented— a very
effective explanatory method.

Computer novices are always assured
that a strong math background is not
necessary for programming. Regardless
of its necessity, a thorough grasp of math-
ematical principles is certainly desirable.
Lien has given the best no-frills expla-
nations of logarithms, exponents, and the
trigonometric functions that I have seen.
If you learn about arrays from this book,
you will wonder why the array is con-
sidered so difficult by some.

The string functions are covered over
several chapters; various concepts are
introduced so slyly— I mean, slowly— that
the reader can easily follow the develop-
ment of an alphabetical sorting routine.

The chapters on video display graphics
develop a simple shoot 'em-down arcade
game that will give you a basic under-
standing and a new respect for the pro-
gramming that goes into the real thing.

All the fundamentals of Sinclair Basic
are covered in what the author notes is a
"light and non-threatening" style— so

Sharon Zardetto Aker, 20 Courtland Dr., Sussex,
NJ 07461.

light, in fact, that he occasionally gets
carried away, leaving one wishing for
something more substantive, e.g., regard-
ing the screech on the tape: "You expect-
ed maybe Lawrence Welk?" or, regarding
the rate/time /distance formula: "If it's
been a few years, you might want to sit on
the end of a log and contemplate that for
a while." The misplaced cuteness is easily
forgiven, considering the contents of the
text and its otherwise excellent presen-
tation.

The author notes that this book is based
on the best of his earlier writings. This
accounts for its quality and also its most
serious flaw— serious in terms of the mag-
nitude of the error, not in terms of the
overall presentation. The chapter on "De-
bugging Programs" has not been thorou-
ghly revised to suit the ZX/TS computers.
He lists some common errors to check
for if your program is not running cor-
rectly. Included here are a half-dozen
mistakes that the ZX/TS syntax checker
never lets you enter to begin with, and it
will even show you where the error is
when you attempt to enter the line, e.g.,
forgotten end quotation marks in a
PRINT statement, using an out-of-range
line number.

There are exercises sprinkled liberally
throughout the book, with sample answers
given at the end. Information is presented
in small doses, in logical sequence, and in
a light manner. You may find yourself
wishing for a little more information in a
particular area, such as how to PLOT a
circle, other PEEK and POKE routines,
or more moving graphics methods.

However, it was not Lien's intention to
teach everything about some things, but
something about everything, and he man-
ages to do just that. It is hard to imagine
anyone working through this book page
by page and not acquiring a thorough
understanding of ZX/TS programming
techniques. It seems an ideal how-to book
for teenagers as well as adults. 5

September/October 1983 « SYNC

Book Review

Mastering Machine Code on Your ZX81

Bruce T. Gar rick

Mastering Machine Code on Your ZX81
by Toni Baker. Reston Publishing Com-
pany. 180 pp. paperback; $12.95.

Though written for the ZX81, Mastering
Machine Code on Your ZX81 applies
equally well to the Timex Sinclair 1000.
Each chapter also includes addressing
and programming procedures for the
ZX80. The light conversational style is
both entertaining and understandable.

The topics covered include: machine
code loader programs, hexadecimal
numbers, assembler mnemonics and
commands. PEEKing and POKEing,
MC storage, the stack, pushing, pop-
ping, negative hexadecimal numbers,
subroutines in MC programs, the ROM
and its many useful routines, music, the
display file, some MC games, ROM dis-

Bruce T. Garrick, 6235 S. Yorktown PL, Tulsa, OK
74136.

assembly, and the use of the ROM
arithmetic subroutines.

Many annotated machine code
routines illustrate the book. Since the
Basic equivalents of the assembler com-
mands are given, you can relate what
you are learning to what you already
know. Each chapter from four on con-
cludes with exercises which are very im-
portant. If you do not do them, you will
miss out on a great deal. However, the
very first exercise could have been eas-
ier. Chapter 9 is worth the price of the
book and more. It has a machine code
program that allows you to List, Write,
Insert, Delete, and Save your MC
programs.

The appendices are excellent and in-
clude: the old and new ROM system
variables with their addresses in hexa-
decimal and decimal, conversion tables
for assembler to hex and hex to assem-
bler, the ZX character set, and another

complete listing of the machine code
editing program.

If you may find the use of hexadeci-
mal throughout the book inconvenient
or cumbersome to use, you can use a
converter program to shift to decimal
when you do your own programming.

Mastering Machine Code on Your
ZX81 is an understandable and enter-
taining guide that can take you, as it did
me, from total ignorance of machine
code to a fair comprehension, provided
you are interested in learning machine
code and willing to invest the time. It
took about a month of my spare time to
work my way through the book al-
though that month was not entirely
frustration free. While I am not quite a
master of machine code, I can now write
machine code to suit my purposes. And,
though my programs may lack the ele-
gance of greater experience, they really
work. H

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Book Review

Sinclair ZX8 1

Timex Sinclair 1 000 Statistics

Lawrence A. Kelly

Sinclair ZX81/Timex Sinclair 1000 Sta-
tistics: Twelve 16K Programs Including
Multif actor Analysis of Variance by A.
H. Wolach and M. A. McHale. K.D.V.-
H.E. Publishers. $11.00. 6 program tapes,
$15; individual program on tape, $1.50.

In the highly variable world in which
we live, we use statistics to help us decide
whether the small sample of the universe
we look at is really representative of the
entire universe. In most cases we want to
know whether this sample is represen-
tative of a process which is better or worse
than the rest of the universe.

Some people, highly critical of sta-
tistics, say that you can prove anything
you want with statistics. Unfortunately,
with the misuse of statistics this can be
true. People who can be fooled by statis-
tical abuses often confuse mathematical
proof with statistical inference. Mathe-
matical proof does not exist outside the
theoretical world of mathematics. In the
real world we must use more devious
reasoning powers. In using statistics we
must always be aware of how that reason-
ing works. Statistics "sneaks in the back
door."

For example, we can never prove that
one mouse trap is better than the other
by statistics, but we can prove, with 95
percent or so assuredness, that the two
mouse traps cannot be equivalent. The
default of this circuitous logic is that the
trap that catches more mice must be
better since we are sure that the differ-
ences between mice caught by each trap

Lawrence A. Kellv. 28 Country wood Dr., Morris
Plains. NJ 07950.

CIRCLE 20 ON READER SERVICE CARD

could be observed by chance alone less
than 5 percent of the time. Technically,
these mental gymnastics are called reject-
ion of the "null hypothesis."

The reason for this background argu-
ment is that the software package from
Wolach and McHale really works.

Many software packages from houses
like Microsoft, Sorcim. Ashton-Tate con-
tain long caveats that they do not guar-
antee the performances of their software
in any specific applications, etc. Perhaps
Wolach and McHale should have in-
cluded a similar warning since people
seem to abuse the application of statistics
more than any other discipline. The pro-
grams can be misused if one does not use
the proper test in the proper circum-
stances.

Although the book has 12 programs, it
has really only two main types of tests,
namely, the t-test and the analysis of
variance.

Clearly the t-test, which tests the distri-
bution about the means (averages) of two
groups to see if they are different by
chance alone, is designed to compare two
groups, e.g., to see if Brand A mouse trap
catches more mice than Brand B under
the same test conditions. In the first t-test
in the book, one can test 5 Brand A vs. 10
brand B, and have a valid test. In the
second test, the measurements must be
equal in number, i.e., paired obser-
vations.

The analysis of variance is to be used
in such cases where Brand A is compared
to brands B, C, D for the number of mice
they can catch. This is a one-way prob-
lem; two and three way analysis allows
for varying such factors as the kind of

September/October 1983 ® SYNC

Statistics looks at a small sample of the universe to help
us decide whether the sample is representative and
better of worse than the rest of the universe.

mouse caught or whether using bread in
the trap is better than cheese.

I entered three or four of the listings in
the book. The convention of underlining
the "tokens" is quite helpful. The tapes
all LOADed the first time (3/4 volume)
with no problem. Each of the 12 programs
worked perfectly as described in the help-
ful examples.

For comparison to Wolach and McHale
I chose a report from "Some Statistical
Methods Useful in Circulation Research"

by Sylvan Wallenstein, Christine L.
Zucker, and Joseph L. Fleiss in Circu-
lation Research, an official journal of the
American Heart Association. The editors
had requested the authors, all biostatis-
ticians, to study the statistical methods
applied in the journal over the years 1970-
80 and to comment on the appropriate or
inappropriate use of statistics. They found
that the t-test and analysis of variance
were the most widely used tests and that
the t-test was the only test used in most

Table 1.
Analysis of Mitral Regurgitant Orifice

Circulation Research. July 1980. p

Areas.

Source of variation
Wolach and McHale

Sum of squares

Mean squares

Dog (row)
Time (column)
Residual
Total

1 600
852.55
107.2

2559.75

3
12
19

400

284. 16333
8.933335

44
31

7761
.8115

Wallenstein et al.

Dog (row)
Time (column)
Residual
Total

1600
852.6

1 07 . 2
2559.8

12
19

400
284.2
8.93

studies reported in the journal to the
almost total exclusion of the analysis of
variance which in most cases was the
more appropriate test. Wolach and
McHale must realize this since they pre-
sent only two approaches to the t-test and
10 to the analysis of variance.

Table 1 describes the results of the
data published compared to the results
from Wolach and McHale 's program. The
test was a randomized block design done
by program BMDP2V (Dixon and Brown,
Biomedical Computing Programs, P ser-
ies, Berkeley: Univ. of California Press,
1977) on an IBM 370 in batch mode
through IBM VSPC and by #7RBKE
(Wolach and McHale) on a kit-built ZX81
in an interactive mode in real time.

The book provides many fine referen-
ces to experimental design and the proper
application of each of the tests in the
package. Students of statistics, or anyone
wishing to know more on the subject, will
find an excellent course of study using
the references listed by Wolach and
McHale, their trusty TS1000. and the
tapes available with the book. Jj

Book Review

The ZX8 1 Companion Paul Grosjean

The ZX81 Companion, by Robert
Maunder, Creative Computing Press, 131
pp., $9.95.

The ZX81 Companion, like other ZX81
books, is totally applicable to the TS1000.
It begins with a chapter on graphics tech-
niques. First the screen field is explained.
Then PLOT and UNPLOT are used to
develop the basic components in graph-
ics: drawing straight lines, using triangles,
circles, parabolas, and ellipses, and
moving a point around the screen. After
the PRINT AT instruction is discussed, it
is combined with INKEYS to create real-
time programs.

For users who want to develop their
own data processing and retrieval sys-
tems. Chapter 2 may be worth the price
of the book alone. String handling and
design of programs to handle data are

September/October 1 983 e SYNC

taken up first and then a program for file
processing is developed using a modular
approach.

Chapter 3 introduces educational uses
with about 10 illustrative programs and
games (including six 16K programs) for
spelling and math, including the use of
grids.

Chapter 4 is intended for the more
experienced programmer who is ready to
delve into the secrets of the 8K ROM and
machine code and put them to work for
him. The heart of this chapter is the two
page list of the starting points for most of
the useful ROM routines and the 1 1 page
ROM disassembly (hex addresses, codes,
and mnemonics). This does not cover the
entire ROM, only the parts most easily
usable by the programmer. The listing is
small, but readable.

Each chapter is well illustrated with
drawings, diagrams, and program listings.

These programs include the program out-
lines, variable lists, and comments. Exer-
cises allow the reader to try out the points
being developed, and answers are given
for self checking. The book is typeset,
including the over 60 program listings.
Although this makes the listings much
easier to read, they do not follow the
screen format of the computer. The brief
index includes program names as well as
topics.

The Appendix is a particularly valuable
section because it deals with the design
and development of a program as a whole
by dividing the task up into a series of
steps and taking the reader through the
process.

This is a book for users who are ready
to move beyond the manual to expand
their use of graphics, to tackle bigger
programs, and to use the ROM more ef-
fectively. EH

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* String search routine to
find words, phrases

» Renumber routine to allow
paragraph insertion

* Inverse video screen
function

* Instructions to use the
string search, line renumber
and inverse video as
utilities for other programs

«■ Lower case-if your printer
prints lower case for
graphics characters

» Block delete function

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Book Review

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CIRCLE 47 ON READER SERVICE CARD

Byteing Deeper into Your
Timex Sinclair 1 000

Sharon Zardetto Aker

Bvteing Deeper into Your Timex Sinclair
1000 by Mark Harrison. John Wiley &
Sons. 160 pp. Softbound. $12.93.

Byteing Deeper into Your Timex Sin-
clair 1000 is catchy title, but do not take
it too literally since the book was origin-
ally written for the ZX81 and retitled.
Nevertheless, the content applies com-
pletely to the TS 1000. More importantly
though, it does not just "byte" deeper
than the User"s Manual, it covers many of
the basics in a more easily digestible
manner.

If you have already had some TS 1000
experience, you might want to skip over
the first few chapters. While they are not
unworthy of study, the real meat begins
with chapter 5.

The first program (p. 35) is a simple
three-liner that fills the screen with what-
ever is input. It will hook you on Sinclair
graphics possibilities, and, if you like what
Harrison can do with INPUT. PRINT,
and GOTO, just wait until you see what
he does with 'INKEYS.

All the commands and functions are
introduced, explained, and used in the 37
illustrative programs. Games run the
gamut from "Dice" and "Baccarat" to
"Destination Saturn" and "Black Holes."
The programs for alphabetizing and line
renumbering will get a lot of use, and you
will want to become familiar with "Word
Processor" before you buy that printer
you have been promising yourself.

Although the explanation of plotting

Sharon Zardetto Aker. 20 Courtland Dr.. Sussex.
NJ 07461.

circles and ellipses assumes the reader
has a knowledge of trigonometry, the
uninitiated can use the formula programs.

The chapter on PEEKing and POKEing
shows how to use the memory locations
in the ROM and the RAM. When you
write your own game programs, you will
return repeatedly to the sample uses of
PEEK and POKE. While the introduction
to machine code will not make you a
machine code programmer, it will help
you understand and use more confidently
the many machine code programs avail-
able for ZX/TS computers.

The brief, but thorough, section on the
logical functions might well be the high-
light of the book. Understanding the true/
false testing capability of the Sinclair will
lead to more elegant programming, and
knowing how to replace lines of
IF/THENs with a concise AND/OR will
save memory.

The last section on "Projects" (hints,
not answers, are provided) is uncomfort-
ably like a final exam. If, however, you
can handle the projects, you will know
that you know your stuff. Harrison knows
his stuff, and he explains it well.

If you were totally lost half way through
your Manual, this book is not the best to
turn to. Although its explanations are
clear and concise, it moves quickly and
does not give you second chances. How-
ever, if you are in need of some clarifi-
cation or if you might benefit from a
different approach, this is a book to buy.
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IK RAM

The Logical Operators

Sharon Zardetto Aker

AND and OR have two distinct us-
ages in Sinclair Basic. One mirrors their
use in English and is easily understood;
the second is less straightforward, but is
an extremely versatile programming
technique. NOT, the third logical op-
erator, is unfortunately overlooked or ig-
nored by many beginner programmers;
it, too, can be a powerful programming
tool.

AND and OR

IF A<10 AND BOO THEN. . .

IF A<10 OR BOO THEN. . .

In the first example, the command
following THEN is executed if both con-
ditions are true (the conditions being
A < 10 and B < 10). In the second exam-
ple, as long as either condition is true,
the command will be executed.

AND has a higher priority than OR
and is performed first regardless of its
position in the conditional statement.
I F X>5 OR Y>5 AND Z>5 THEN . . .

This statement sets up two conditions:

1) X>5

2) Y>5 AND Z>5

Since they are linked by OR, either one
being true will cause the command to be
executed.

To circumvent the computer's auto-
matic ordering of operations, paren-
theses should be used.
I F ( X>5 OR Y>5 ) AND Z>5 THEN . . .

The two conditions in this statement
are:

1 ) X>5 OR Y>5

2) Z>5
Since they are linked by AND, both con-
ditions must be true for command
execution.

You should note that, in this last

Sharon Zardetto Aker. 20 Courtland Dr , Sussex, NJ
07461

You must understand the computer's
view of "truth": a true condition is

1 ; a false condition is .

example, there are actually two combi-
nations that will satisfy the computer's
truth-check:

1 ) X>5 AND Z>5

2 ) Y>5 AND Z>5

Instead of IF-THEN

AND and OR also have another, en-
tirely different, usage in Sinclair Basic,
one that allows you to combine several
IF-THEN statements into one logical
statement that does not even use IF-
THEN.

IF AO0 THEN GOTO 125

IF A=10 THEN GOTO 300

IF A>10 THEN GOTO 480
can be rewritten:

GOTO (125 AND AO0) +
(300 AND A=10)+
(480 AND A>10)

To translate this into understandable
English, read each AND as "if." The
computer looks at each one of the par-
enthetical statements and checks the
truth of the expression following AND.
If that conditional statement is true, the
value of the parenthetical statement is
set at whatever precedes AND; if the ex-

pression is false, the statement is as-
signed a 0.

So in this last example, if A is 14, the
line will work out as in Figure 1. The
computer will GOTO 480.

Mutual Exclusivity

The parenthetical statements in the
above example are mutually exclusive;
that is, if one is true, the others have to
be false. That is not always the case, and
you should plan carefully in a situation
like the following:

IF NO0 THEN GOTO 100

IF N=10 THEN GOTO 150

IF N<20 THEN GOTO 200

Obviously, N can be less than 10 and
less than 20 at the same time; so can it
be both equal to 10 and less than 20. As
long as the IF-THEN statements are in
the right order in your program ("right"
depends on the effect you want), there is
no problem because the computer will
act upon the first true statement it en-
counters and never see the one(s)
following.

However, if you rewrite these state-
ments using the logical operators, you

Figure 1.

GOTO ( 125 AND AO ) +

false
GOTO ( ) +

(300 AND A=10)

false

(0)

(480 AND A>10)
true
(480)

Figure 2.

GOTO ( 100 AND NO )

false
GOTO ( )

( 150 AND N=10)
t r ue
(150)

(200 AND N<20)
true
(200)

September/October 1983 « SYNC

would have a big problem. If N is 10, the
computer would make the evaluation
found in Figure 2 and execute GOTO
350.

Further definition of one or more of
the conditions, until the parenthetical
statements are mutually exclusive, is
necessary. For instance:

IF N<10. . .

IF N=10. . .

IF N<20 AND N>10. . .

Written logically,

GOTO ( 100 AND N<10)+
( 150 AND N=10)+
(200 AND (N<20 AND N>10))

In the last parenthetical statement,
the first AND operates as "if." The sec-
ond AND operates in its usual manner
requiring that both conditions be true
for the total expression to be true. The
inner parentheses are not strictly nec-
essary, since the first AND will always
be used as the "if; they were included
here only to make the example clearer.

Other Commands

Since the entire logical expression
boils down to a number, it can be used in
place of a number with many different
commands:

PRINT AT (5 AND Z>14)+

(2 AND Z<5) , 10; ' 'OKAY' I
PLOT X, ( 17 AND B=12)+

(27 AND B<>12)
GOSUB (500 AND L=10)+

V O <J V Ml NL-» ivi= l \J )

PRINT (0 AND N<>10)+

(N AND N=10)
PAUSE ( 120 AND T<10)+

(380 AND T>=10)

Strings

Strings can also be used with logical
statements. If the conditional expression

is true, the parenthetical expression is
"equal to" the string before AND. If the
conditional expression is false, the state-
ment is considered to be an empty
string. So:

I F A>B THEN PR I NT ' ' TOO H I GH ' '
I F A<B THEN PR I NT " TOO LOW ' '
can be rewritten as:
PRINT ( ■ 'TOO HIGH' ' AND A>B)+

( ' ' TOO LOW ' ' AND A<B )
When A is larger than B, the statements
will be evaluated:
PRINT ( ' 'TOO HIGH' ' )+(■''' )

You can also assign a string value
with this syntax:

LET P$=( ' 'TOO HIGH' '
AND A>B)+
( ' ' TOO LOW ' ' AND A<B )

A logical expression for strings or
numbers does not have to consist of
alternative choices; a parenthetical logi-
cal expression can be inserted into
an otherwise straightforward command.
Consider a program that would display a
multiplication problem of two randomly
generated numbers (A and B) and a
player's answer (C). If the answer is
wrong, you might want it marked with
an asterisk.

PR I NT A ;''••'; B ;
TAB 1 ; ( ' ' * ' '
AND COA-B) ;TAB 11 ;C

If the answer is correct, nothing will
be printed at TAB 10.

Variable Re-valuation

Logical expressions that change the
value of a variable are easy to use. Here
is one example, and the ways it would be
evaluated.

LET X=X+(5 AND B<A) + (7 AND B>A)
I f B<A X+ (5) + (0) =(X+5)
I f B>A X+ (0) + (7) =(X+7)
I f B=A X+ (0) + (0)=(X)

As you can see, there is no need to
write a statement for the B = A possibil-
ity if you want X to remain the same in
that situation.

If the variable is to be decremented,
change the plus sign to a minus sign:

LET N=N+(5 AND P=0)-
(5 AND POO)

This will be evaluated in one of two
ways:

I f P=0 : N+(5)-(0) = N+5

I f POO: N+(0)-(5) = N-5

Using OR

While AND is used for strings and
numbers, and variable re-valuation
involving addition and subtraction, OR
is only practical for re-valuations involv-
ing multiplication or division. A study of
the chart in Figure 3 might help you
understand why this is so.

When OR is used in this construction,
read it as "unless":

LET N=N«(10 OR A>B)

If B is less than A, the statement is
true. It is evaluated as 1 (as noted in the
chart), and reads:

LET N=N«( 1 )
and the value of N does not change.

If B is not less than A, the parentheti-
cal statement is assigned the value of the
number before OR:

LET N=N«( 10)

So, N is multiplied by 10 unless B is
less than A, in which case N remains the
Same.

If you were writing a program to cal-
culate new prices for merchandise going
on sale, where items less than $100 were
to be reduced by 10% and all others by
20%, your statement would read (P is
the current price):

LET P=P«( .8 OR P<100)«
( .9 OR P=100)

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The evaluations are:
I f P<100: P<

I f P>=100 : P>

(1)(.9) =P«.9
( .8)(1) =P«.8

Non-exclusive Statements

You may not always want parentheti-
cal statements in a variable re-valuation
to be mutually exclusive.

Consider a game where a player re-
ceives 10 points for hitting at least ten
targets, and a bonus of 20 points for hit-
ting exactly ten targets.

LET SCORE=SCORE+
( 10 AND H>9)+
(20 AND H=10)

When H is ten, both expressions are
true and SCORE is incremented by 30
points.

ORs do not have to be mutually
exclusive, either. Consider the change in
a game score caused by the following:

LET S=S«(10 OR H<5)«
( 10 OR H<10)«
(10 OR H<15)

If H is less than five, all three state-
ments are true, evaluated as 1, and S (the
score) does not change at all. As the
value of H gets higher, the score will be
multiplied by 10, 100, or 1000, depend-
ing on how many of the parenthetical
statements are true:

I f H
S=S

is 7 :
■(10)«
is 12
■(10).
is 19
(10).

(1)«(1) =S«10

( 10)« ( 1 ) =S* 100
( 10). ( 10) =S«1000

NOT

To make use of NOT, you must first
understand the computer's view of
"truth." Conditions in an IF-THEN
statement are evaluated, and a true con-
dition is assigned a one, while false one
are assigned zero. (Note the "result" col-
umn in Figure 3.)

Furthermore, any mathematical ex-
pression whose result is zero is consid-
ered false, while a non-zero result (even
a negative number) is true.

NOT changes the true/false value of
an expression:

If A is false, NOT A is true.

If A is true, NOT A is false.

Applications

If you would like a command exe-
cuted every second time it is en-
countered in a loop, use NOT to change
the true/false value of a variable back
and forth. With:

I F V THEN . . .
at the beginning of a loop, and:

LET V=NOT V
later in the loop, V will be true on every
other loop.

By using

LET E=N/2-INT(N/2)
E is zero whenever N is an even number.
To have a command executed only when
N is even, use

I F NOT E THEN . . .

Similarly,

LET l=N-INT N
means that I is zero whenever N is an
integer, and

I F NOT I . . .
will be a true condition when N is a
whole number.

Priority

NOT is assumed to apply only to the
number to its right, unlike the other
logical operators, which automatically
apply to an entire expression.

NOT B<C
is interpreted as:

(NOT B)>C

NOT has priority over both AND and
OR, so the following conditional state-
ment would be processed in the order of
innermost brackets first:

IF [ [ [NOT A] AND B] OR C]

The use of NOT can, of course, be al-
tered by the use of parentheses.

A Demonstration Program

"Dots" is a sketcher program that
illustrates the use of the logical ex-
pressions to change the value of a
variable.

You will be drawing with colons in
this program, which gives an interesting
effect, since a double row of dots is
printed when you move horizontally,
and a single row if you move vertically.
You can also move diagonally, and if
you go off the edge of the screen, the line
will continue from the opposite edge.

. Figure 3. .

Operator

Conditional
Choice

Conditional
Expression

Result

AND
AND

A$
A$

true
false

( emp

A$
it it

y s t r

ng)

AND
AND

N
N

t r ue
false

OR
OR

N
N

true
false

1
N

September/October 1 983 « SYNC

The keys surrounding F on the keyboard
control the movement: T is for straight
up, V for diagonally down to the left,
and so on. Pressing G will stop the
program.

Line Notes

20,30: Set initial value of L (line num-
ber) and C (column number) so colon is
printed in screen center.

80,90: Change line and column num-
bers according to which key has been
pressed. The AND in the parenthetical
statements operate as "if." The ORs op-
erate in the basic manner.

100,110: Reset the line and column
numbers if the new values result in a

REM C'CT-

REM E , ZfiRr. E — : -- EC

_ET L=ll

ft c = 3 5

■ a

DDTWT -■ —

IF I'.- EY*= THEN SOTO 50

-E T : *

IF M$ = C- THEN 5TOF

_E^ L*L+ (J RNC M$= E : - M$

= T;

DR M*= U - - RNC M$= -

'•' T =

OR M$ =

lE t C sC+ U RNC M$= OR M*

= M

OR M $ a N - - RNC M $ = F

M* =

OR M*i

100

_E~ L=L+C22 RND L = -l - 122 fl

NC _

= ;;

110

LCI _=L-.-i -'■_ _=-_ - j- -

-32 !

120

JOT0 4-0

number that would not be on the screen.
If L is — 1, adding 22 to it makes it 21,
and places the print position at the op-
posite edge of the screen; if L is 22,
subtracting 22 puts the print position at
zero.

You should note that the diagonally
drawn lines result from L and C chang-
ing on the same loop. 5i

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IK RAM

Memory Scrunching on the TS1 000 and ZX8 1

James Grosjean

One of the most serious problems that
TS1000 users are faced with (and ZX81
users even more so) is the lack of memory
(RAM). Most commercial programs re-
quire a 16K RAM pack, and many printed
in newsletters and magazines require over
2K (or IK for ZX81 people). Although
the package or listing calls for 16K, this
does not mean that the program is 16K
long. It just means that you must have
more RAM than your machine comes
with and 16K is the next increment.

If you do not intend to expand your
system RAM, the only solution is to short-
en programs which might fit then into
your RAM.

This article collects over thirty tips to
save memory. Some of them have ap-
peared in SYNC; hopefully some of them
are new to you. Some are simple, obvious
hints, while others require some clever
programming. When dealing with 2K (or
less) every byte counts!

You can calculate the bytes in the
various lines as follows: Line numbers
take up two bytes no matter whether the
number is 1 or 9999. Between the line
number and the text of the line in the
computer's memory are two bytes telling
the computer how long that line is from
the first byte of the text of the line up to
and including the end of line marker
(CHR$ 118). In the line itself all letters,
keywords, etc., typed by a single key-
stroke take up one byte except numbers.
Numbers take up six bytes plus the num-
ber of digits and one byte for the decimal
point if any. After the text of the line is an
end of line marker telling the computer
where the line ends. This marker takes
one byte.

lames Grosjean, 50 Kings Rd.. Chatham. NJ
0792R.

program may require the 16K RAM
pack, but that does not mean it uses 16K RAM.

Memory Scrunching Tips

1) REM statements

Eliminate REM statements and include
them in your documentation.

2) Game elements

Eliminate one or more game elements.
This might make the game fit into 2K.

3) Restart mechanisms

Omit restart mechanisms completely.
E.g., "Do you want to play again? Y or

N."

4) STOP statements

If the last program line is a STOP
statement, delete it. The program will
stop anyway only with a different error
code.

5) Keywords and tokens

Use keyword and token expressions.
When entering a line such as:

10 REM TO RUN USE GOTO 100
use the keywords for the words TO, RUN,
and GOTO. This line is entered by typing
exactly: 10, E (REM), SHIFT 4 (TO),
SHIFT 3 (THEN), R (RUN), SHIFT 5
(BACKSPACE), SHIFT (DELETE
THEN), SHIFT 8, U, S, E, SHIFT 3
(THEN), G (GOTO). SHIFT 5 (BACK-
SPACE), SHIFT (DELETE THEN),
SHIFT 8, 1, 0, 0, ENTER. Do this several
times to gel used to it. If necessary, re-
word prompts to allow for this technique.

6) PRINT statements

Shorten or eliminate PRINT state-
ments, and include the information in

your documentation in a notebook for
programs. For example, replace A with
B.

A: 10 PRINT "DATE OF BIRTH?"

B: 10 PRINT "BIRTHDATE?" or
"BORN?"

7) Commas

When lining up PRINT lines, use com-
mas or hyphens instead of spaces. For
example, replace A with B or C.

10 prini

0U : .'I:- TO FIGH1
PIPEDE 3B FLEE?'

Ifl PRINT DO DU JISH TO FIG
"-5 , CENTIPEDE J- = L=.5 _

10 PRINT LC DU JISH _ C fig

rME denti- =ec£ dr flee?

8)PRINTATs

Combine PRINT AT's into one line.

For example, replace
10 PRINT AT2,14;"HI"
20 PRINT AT 5,12:"THERE."
30 PRINT AT 8,12:"SALLY"

with

10 PRINT AT 2,14;"Hi";AT 5,12;

"THERE,";AT 8,12;"SALLY"

9) Combine lines

Rearrange programs to allow for a com-
bination of lines. This can change the
results of the program so be careful. For
example, replace

50 IF Y=9 THEN STOP

60 INPUT 1$

70 IF I$="YES" THEN STOP

80 GOTO 20

September/October 1 983 ® SYNC

with

50 INPUT 1$

60 IF Y=9 OR I$="YES" THEN
STOP

70 GOTO 20
Remember to change GOTOs and
GOSUBs to their new line numbers.

10) Parentheses

Eliminate unnecessary parentheses. For
example, replace A with B.

A: 10LETI=(A*10)+(B»5)

B: 10 LET I=A»10+B*5
Because of the order of operations (refer
to manual) this will be evaluated
properly.

11) Conditional statements

In certain cases a condition can be
changed without changing the effect. For
exHm n !e r? n !?c? A with B.

A: 10 IF Y= 10 THEN PRINT "YOU
KILLED IT."

B: 10 IF Y>9 THEN PRINT "YOU
KILLED IT."
This saves one byte because 9 has only
one digit. However, if floating point num-
bers are utilized in the program, this tech-
nique may not work.

12) Variable names

Do not use words for variables. Replace
A with B.

A: 10 LET STRENGTH= 10

B: 10LETS=10
Include variable descriptions in your doc-
umentation.

13) IF...THEN STOP

If a line contains a conditional jump to
a STOP statement, replace it with an
IF...THEN STOP statement. For example,
replace

100 IF Y < 10 THEN GOTO 400

400 STOP
with
100 IF Y < 10 THEN STOP

14) Arrays

Do not set up an array with more ele-
ments than needed. If 54 elements are

reniiirw, iitp FIIM A(<ii) n.itlllMAlHIl
1 » v- ■/» --\ /-

15) in arrays

Eliminate statements which initially set
array elements to 0. For example,

10 DIM A(4)

20LETA(1)=0

30LETA(2)=1

40 LET A(3)=0

50 LET A(4)=9
Delete lines 20 and 40. After execution of
line 10 all elements are set to auto-
matically.

16) CLEAR

Try to use the CLEAR command if
possible. CLEAR can sometimes save a
program just before it runs out of mem-
ory. CLEAR is one of the least used
commands in Basic.

17) GOTO/CLEAR

In very rare cases RUN can replace a
GOTO/CLEAR combination. For
example:

65 CLEAR

70 LET A =7

175 GOTO 65
Delete line 65 and change 175 to 175
RUN 70. Because RUN clears all vari-
ables, it can replace a CLEAR and a
GOTO.

18) One time variables

If a variable is only used once do not
assign the variable. For example, replace

10 LET D=INT (RND*10)+1

20 FOR 1=1 TOD

30 PRINT "a"; (inverse space)

40 NEXT I
with

10 FOR 1= 1 TO INT (RND*10)+ 1

20 PRINT "■"; (inverse space)

30 NEXT I
This allows you to delete a line (with a

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slight lengthening of another) and not
assign an unneeded variable.

19) Reuse variables

Reuse variables. Once a variable has
been assigned it remains in memory, even
if it is not used again in the program
(unless RUN, CLEAR, or NEW is used).
Look at this program:

10FORX=lTO10

20 PRINT " ";

(10 inverse spaces)

30 NEXT X

40 LET D=INT (RND* 10)+ 1

50 PRINT "YOUR STRENGTH IS
";D

The variable X will take up memory until
RUN, CLEARed, or NEWed. Even
though no longer used, it occupies pre-
cious bytes of RAM. A better program
would be :

10 FOR X=l TO 10

20 PRINT " ";

( 10 inverse spaces)

30 NEXT X

40 LET X=INT (RND»10)+1

50 PRINT "YOUR STRENGTH IS
";X

Now, instead of both X and D stored in
memory, only X is in memory.

20) Reuse variables without reassign-
ment

In certain cases a variable can be re-
used without being reassigned. For
example:

10 FOR X=l TO 10

20 PRINT " ";

( 10 inverse spaces)

30 NEXT X

40LETX=11

50 PRINT "YOU NOW HAVE ";X;"
GOLD PIECES."

Line 40 can be deleted. After completing
the loop X is already equal to 11. How-
ever, not many variables are initially set
to 11; ten is more likely. Thus:

21) FOR-NEXT variable range
Replace the previous example with:
10 FOR X=0 TO 9

20 PRINT " ";

(10 inverse spaces)

30 NEXT X

40 PRINT "YOU NOW HAVE ";X;"
GOLD PIECES."

After the loop X equals 10, which is easier
to work with than 11. This also saves
memory. The number of bytes needed to
store an integer equals the number of
digits plus six. In line 10, the use of and
9 saves one byte in place of 1 and 10,
because 10 has two digits and 9 has one.
Compare:

Tip 21:

0=1+6 = 7 bytes
9=1 + 6 = 7 bytes
for a total of 14.

Tip 20:

1 = 1+6 = 7 bytes
10 = 2 + 6 = 8 bytes
for a total of 15.

22) Number substitutes

Because numbers require a minimum
of seven bytes of memory, too many num-
bers quickly fill up the RAM. Therefore,
replace line A with line B below.

A: 10 LET E=0

B: 10 LET E=NOT PI

requires 7 bytes; NOT PI uses 2 bytes.
Some other expressions for are USR PI,
SIN PI, and TAN PI, each requiring two
bytes.

A: 10LETE=1

B: 10 LET E=SGN PI

1 requires 7 bytes; SGN PI uses 2 bytes

A: 10LETE=3
B: 10 LET E=INT PI
3 requires 7 bytes; INT PI uses 2 bytes
Some other expressions and their equiv-
alents are:
COS PI = -1
PEEK PI = 255
PEEK NOT PI = 211
PEEK SGN PI = 253
PEEK PEEK PI = 135
LEN STR$ PI = 9
CODE STRS PI = 31
This list is by no means complete.

For any other numbers use VAL (see
tips 23 and 24 for exceptions) as shown in
B below to replace A.
A: 10 LET E=2
B: 10 LET E= VAL "2"
A: 10 LET E=327
B: 10 LET E= VAL "327"
In each case the use of VAL saves three
bytes. Note:
2 = 7 bytes
VAL "2" = 4 bytes
I have yet to find a better expression to
replace VAL "2".
327 = 9 bytes
VAL "327" = 6 bytes
This tip is used not just in assigning
variables. One of the above methods can
be used to substitute for a number any-
where a number is used.

However, do not put VAL around each
number in an expression:

10 LET E=(INT (RND* VAL
"10")+VAL "5")*VAL "100"
Instead put VAL around the entire ex-
pression:

10 LET E=VAL "(INT (RND»10)+5)
•100)"
This way you get the most out of VAL.

Remember, though, that extensive use
of VAL, NOT PI, etc., can slow down a
program tremendously, but that is the
sacrifice for memory saving.

23) VAL exception

An exception to the use of VAL is
sometimes encountered:

10 FOR X=NOT PI TO VAL "20"

September/October 1983 c SYNC

VAL "20" uses five bytes. If this line is
replaced with:

10 FOR X=NOT PI TO EXP INT PI
rwn b v tes ma v be saved. EXP INT PI
uses only three bytes. Although EXP INT
PI = 20.085537, this is rounded to 20
when used in combination with FOR. This
means that in the revised program in tip
18, the INT in line 10 may be deleted.
EXP PI could substitute for the number
23 using the same method.

24) Variable instead of VAL

Another exception is when a single
number is used many times. Assign a
variable to it instead of using VAL. For
example, replace

20 IF I > 10 THEN GOTO 80

22 INPUT 1$

24 IF I$="FIGHT" THEN GOTO 80

ioirrt^ou i ntn uu i \j utuu

28 LET U=B+80

30 IF U/T > 80 THEN GOTO 251

with

10 LET Y=80

20 IF I > 10 THEN GOTO Y

22 INPUT 1$

24 IF I$="FIGHT" THEN GOTO Y

26 IF A > Y THEN GOTO Y*Y

28 LET U=B+Y

30 IF U/T > Y THEN GOTO Y*PI

25) Strings in PRINTs

Similarly, if the same set of characters
must be PRINTed several times, assign a
strin° variable to those characters and
PRINT that string. Keep in mind that it
takes up memory to assign the variable as
well as to keep the variable in the variable
storage of the computer. So use this
method only when the string must be
PRINTed enough times to make it worth-
while.

26) Destination changes
Change GOTO (or GOSUB)
tinations. For example:
10 GOTO 100

des-

100 PRINT
DRAGON"

"YOU FACE

Line 10 can be changed to 10 GOTO 99
and take advantage of a characteristic of
the TS1000, namely, that, if the GOTO
or GOSUB destination line does not exist,
the computer skips over it and goes to the
next line. Thus in the example above, the
computer, finding no line 99, will go on to
100. This saves one byte since 99 has two
digits, not three.

27) Calculated destinations

The following is often seen in a pro-
gram:

!00 IF 1=1 THEN GOTO 1000
110 IF 1 = 2 THEN GOTO 2000
120 IF 1=3 THEN GOTO 3000
130 IF 1=4 THEN GOTO 4000
This can be replaced with a calculated
GO TO. For example:
100 GOTO 1*1000

If your program is not numbered to
allow a calculated GOTO, renumber it,
or:

28) Logical destinations

Use a bit of logic. For example, the

following lines:

10 IF 1=1 THEN GOTO 100
20 IF 1=2 THEN GOTO 219
30 IF 1=3 THEN GOTO 235
40 IF 1=4 THEN GOTO 900

can be replaced by:

10 GOTO (I=1)*100+(I = 2)*219+(I

=3)*235+(I=4)*900

Of course, we could use VAL around that

expression.

10GOTOVAL"(I=1)*100+(I=2)»

219+(I=3)*235+(I=4)*900"

29) Logical combinations

Use logic to combine statements. For a
detailed discussion of the logical oper-

Forthe TS1000/ZX81

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ators and techniques see Sharon Aker's
article in this issue.

30) Replacements
Replace A with B:

A: 10 IF Y=0 THEN...
B: 10 IF NOT Y THEN...
A: 10IFYO0THEN...
B: 10 IF Y THEN...

31) Shortened restarts

This is a very impressive tip. Many
games have a restart mechanism. For
example:

810 PRINT "ANOTHER GAME?
(Y/N)"

820 INPUT A$

830 IF A$="Y" THEN RUN
This can be shortened, but a few simple
adjustments are needed:

Change 820 to 820 INPUT A
Change 830 to 830 RUN
and make sure one of the program's vari-
ables is Y and none are N. Then, if "Y" is
entered in response to the prompt in line
810, the computer will accept that as a
legitimate response (because of the ex-
pression evaluator) and continue to line
830, where the program will be RUN. If
"N" is entered, the computer will stop
with an error code 2/820. This is what
your final program would look like:

10 LET Y= 10

810 PRINT "ANOTHER GAME?
(Y/N)"

820 INPUT A

830 RUN
Do not add a line in assigning the variable
Y. Change one of the other variables in
the program to Y. It is presumed that line

10 above had previously used a different
variable such as 10 LET A=10.

32) False saving

There is one technique which some
programmers use in an attempt to save
memory, but it actually wastes memory
instead. Lines such as these:

10 PRINT "YOU HAVE NO

STRENGTH"
20 PRINT

are replaced with

10 PRINT "YOU HAVE NO

STRENGTH",,
and then line 20 is deleted. This appears
to save 4 bytes. Actually it wastes mem-
ory. The PRINT statement puts an end of
line marker into the display file. There-
fore a blank line on the screen takes up
one byte when created by a PRINT used
by itself as in line 20. When a comma is
used, the computer fills the display file
with spaces until the proper print position
is attained. So it is better to have a
slightly longer program than a much larg-
er display file.

When all these tips are used, a program
can often be reduced by as much as 50
percent. Note that in many of the above
examples the revised program lines can
be shortened even more by using some of
the other tips in this article, but that would
make the examples confusing.

Speed Tips

Along with the problem of memory,
TS1000 and ZX81 users often complain
about speed. Here are a few tips to in-
crease the speed of a program:

I) Unnecessary calculations
Eliminate unnecessary calculations.
VAL, NOT PI, and other memory savers

slow down the program. Replace A with
B.

A: 10LETU=Y*20/4*X

B: 10 LET U=Y»5*X

2) Unnecessary lines

Delete unnecessary lines, e.g., REMs.

3) Eliminate GOTOs

Rearrange the program to eliminate as
many GOTOs as possible.

4) Subroutines upfront

Subroutines used often should be lo-
cated as near the beginning of the pro-
gram as possible. When the computer
comes across a GOTO or GOSUB, it
searches for its destination line from the
beginning of the program.

5) Redundant GOTOs
In situations like this:

30 GOTO 180

180 GOTO 90
Change 30 to 30 GOTO 90.

6) Arrangement of variables

Assign the variables that are used the
most first. When the computer comes
across a variable, it searches through its
variable area from the beginning to the
end. Variables are stored in the order
that they are assigned.

As a general rule, speed is often given
up for memory saving and vice versa,
unless machine language is used. Machine
language is FAST and short.

This collection of memory saving tips
is by no means complete. If you can add
to the collection, send your tip to SYNC.
Be sure to give examples. 5

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FOR/NEXT

LET

IF/THEN

GOTO

GOSUB/RETURN 7YJ

PRINT A °S

LPRINT pGN

PLOT/UNPLOT

r \^i> \ i_

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PAUSE

CLS
COPY
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the REM statements to store important
telephone numbers, dates, appointments,
birthdays, etc. They could also hold in-
ventories, screen coordinates for plot-

ting, machine code, or words like
"CAT" and "DOG" for a computer ver-
sion of "Hangman."

Listing 7 is an example of a computer

. Figure 2. Restore and READ Siring Routines.

Assembly Listing

RESTORE LD HL. 16634
FIND LD A, CODE "REM"

LD BC, 65536

CPIR

LD BC,5

AND A

SBC HL,BC

LD A, 118

CP (HL)

JR Z. BELOW

ADD HL,BC
STASH LD (16507),HL

RET
BELOW ADD HL,BC

JR FIND
READ
CHARACTER LD HL, (16507)

LD A, IIS

CP (HL)

CALL Z,FIND

LD A, (HL)

INC HL

JR STASH
READ
STRING LD HL, (E-LINE)

DEC HL

PUSH HL

DEC HL

EX (SP),HL
LOOP PUSH HL

CALL READ

CHARACTER

POP HL

LD B,CODE", "

CP B
COMA DONE JR Z , DONE

LD (HL),A

INC HL

EX (SP),HL

INC (HL)

JR NZ,NO CARRY

INC HL

INC (HL)

DEC HL

EX (SP),HL

AND A

JR NC,LOOP
DONE EX (SP),HL

POP HL

NOP

JP ROM

INC LEN*

NO CARRY
DO MORE

Address
16514
16517
16519
16522
16524
16527
16528
16530
16532
16533
16535
16536
16539
16540
16541

16543
16546
16548
16549
16552
16553
16554

16556
16559
16560
16561
16562
16563
16564

16565
16568
16569
16571
16572
16574
16575
16576
16577
16578
16580
16581
16582
16583
16584
16585
16587
16588
16589
16590

Machine Code

33 250 64
234
255
177

237

167

237

190

201

190

204

126

229

227

229

205

225
6

184
40

119
35

227
52
32
35
52
43

227

167
48

227

225
O

195

25S

66
118

123

230

123
118

236

159

23:

157

Figure 3. FREE MEMORY Routine. .

Assembly Listing

Address

Machine Code

FREE MEM LD HL, (STKEND)

16593

28 6

LD B,H

16596

LD C,L

16597

LD HL,0

16598

ADD HL,SP

16601

CP A

1 6602

191

SBC HL,BC

1 6603

237

LD B,H

1 6605

LD C,L

16606

RET

1 6607

201

Checksum

347
643
1154
1568
1574
1741
2044
2224
2414
2459
2468
2689
2890
2899
3153

3382
3562
3752
4053

4179
4214
4474

4600
4643
4872
4915
4958
5185
5414

5842
6067
6099
6283
6336
6455
6490
6717
6769
6804
6839
6891
6934
7161
7328
7609
7836
8061
8061
8433

Checksum

8567
8635
8712
8745
8802
8993
9296
9364
9441
9642

telephone directory that runs in IK. The
other ideas mentioned above I will leave
as exercises for interested programmers.
Feel free to substitute other phone num-
bers in line 10. This same program can
be used to store other kinds of data
where one item is directly related to an-
other. An English to Spanish translator
would be an example.

Listing 8 will graph any function you
give it. First, you must input the func-
tion in terms of X. For example, if you
wanted to graph (f(X) = 4X z + 3X + 2)
then you would input 4*X*X + 3*X + 2.
Then you have to input the lower and
upper limits on X. If you were plotting a
sine curve, for example, you would prob-
ably want to use limits of zero and two
pi. The nice thing about this program is
that the vertical limits are calculated
automatically. This makes function plot-
ting quite a bit easier.

Stored on REM statements are some
functions you can select instead of your
own. Each function is followed by its

Listing 4.

i snuc -listing *••

a LPRINT "LISTING *",,,, "USE
FIRST TUO LINES ONLY UTTH EXPAN5
ION MEMORY", ,,, "GRAPHICS KEYS If.
LINE 3B 53HTY5T55885E«U64a61YT
58",,

3 LLIST IB

4 LPRINT " SLOU " , , " GOTO 0"

5 STOP
IB POKE 16389,68
28 CLS

"9", URL "S"i "1

UAL "10-.UAL -a"

_ _. AT UAL "ll",UAL

10 FOR Z-NOT Pi TO CODE "♦"

5a unplot z«-z,z

S3 UNPLOT Z+Z+SGN PI, CODE "F -

68 NEXT Z

63 RAND USR IU

70 GOTO CODE "Z"

Listing 5.

29 CLS

38 PRINT AT UAL

4 a FOR Z-NOT PI

1 SfWE "LISTIMS 5"

2 LPRINT "LISTING S'

3 LLIST 10

+ LPRINT " GOTO B~

S STOP
10 POKE 16339,255
20 CLS
30 SLOU

40 RAND USR IU
50 FOR R=l TO 39
60 NEXT A
70 GOTO 4.0

Listing 6.

1 5RUE "LISTING 6"

a LPRINT "LISTING 6",,,,

3 LLIST 10

4 LPRINT " SLOU " , , " GOTO I

5 STOP

19 FOR Z=NOT PI TO CODE " < "

30 PRINT TAB CODE "3"

39 NEXT Z

10 RAND USR IU

S9 GOTO CODE "A"

Listing 7.

1 SRUE "LISTING 7"

2 LPRINT "LISTING 7",,,,

3 LLIST 10

4 LPRINT " GOTO 0"

5 STOP

10 REM JOHN, 7S2-51B6, MIKE, 752
5379 , CRUMP , S9S -4809 ,

20 PRINT " INPUT NAME"
30 INPUT fl»

49 RAND USR RS

50 LET 8* = ""
60 RAND USR RD

70 IF B*="DATA OUT" THEN GOTO
■ t^l. "20"

60 LET C*=""
90 RAND USR RD
100 IF Btcflt THEN GOTO UAL "50

110 PRINT C*

120 GOTO UAL "20"

130 REM DATA OUT,

September/October 1983 • SYNC

Figure
Assembly Listing

4. INSTANT REVERSE Routine.

Address

Machine Code

Checksum

IV LD HL, (D-FILE)

1 6608

12 64

9760

LD B,H

16611

9828

LD C,L

16612

9905

LD D,59

16613

9986

SLA D

16615

203

10223

LOOP LD HL, (VARS)

16617

16 64

1 0345

LD A, <BC>

16620

10355

CP D

16621

186

10541

JR Z, AGAIN

16622

10584

ADD A, 128

16624

198

128

10910

LD (BC),A

16626

10912

AGAIN INC BC

16627

10915

CP A

16628

191

11106

SBC HL,BC

16629

237

1 1 409

JR NZ,LOOP

16631

240

11681

RET

16633

201

11882

tiRlirr 1. RE31W:ATiiMi

nomine

Assembly Listing

Address

Machine Code

Checksum

RELOCATE LD HL, <RAMTOP) 16634

4 64

11992

LD BC,-120

16637

1 36 255

12384

ADD HL,BC

16640

12393

PUSH HL

16641

229

12622

PUSH HL

16642

229

12851

EXX

16643

217

1 3068

POP BC

16644

193

13261

EXX

16645

217

13478

LD HL, 16514

16646

130 64

13705

POP DE

16649

209

13914

LD BC, 120

16650

120

14035

LDIR

16653

237

176

14448

EXX

16655

217

14665

DEC BC

16656

14676

OUT 2S3,A

i6657

211

253

15140

JP NEW

16659

195

203 3

15541

1 loins ft.

SPUE "LISTING 8"

230

GOSUB URL "400"

LPRINT "LISTING 8",.

S4B

GOTO

URL " 30 "

LLIST 10

300

RRND

USR RS

LPRINT " GOTO 0"

310

FOR R=URL "-2" TO URL "10"

STOP

320

FOR B=NOT PI TO

URL "24" ST

LET F=SGN PI

EP URL "8-

GOSUB CODE " COPY "

330

LET R*=""

IF F THEN PRINT "FUNCTION-

IF B

OR R<NOT PI

THEN RRND

INPUT R*

JSR RD

IF F THEN PRINT "LOWER

IF NOT B AND R > -

SGN PI THEN

LET

R»=STR» R
PRINT TRB B-n*.

INPUT X

360

45
T"

IF F THEN PRINT "UPPER LIMI

NEXT
NEXT

B
R

50
60

INPUT O
LET K=X

390

REH fJI,5ELECT,0PTI0N,t»».0

PTION,FN,RnNGE,, INPUT ,YOUR,OUN

70
80
85

FRST

IF F THEN CLS

LET F=NOT PI

FN,
400
420

INPUT B

IF NOT B THEN RETURN

90
100
110
ISO

LET DX= (R-X) -'CODE "Z -

LET H=URL n*

LET L=H

FOR I=NOT PI TO CODE

4 30

440

450

..... 460

*- 4~7A

RRND USR RS

FOR R=SGN PI TO

LET R*=""

RRND USR RD

NEXT R

FOR R=-SGN PI TO

URL "3*B+8"

130

IF H<URL R* THEN LET

H=URL ll%

SGN PI

431

LET B«=""

140

IF L>UHL H* THEN LET

L=URL 500

RRND

USR RD

•=1*

510

IF R<NOT PI THEN

LET R*=B*

ioa

LEI X=.<+DX

520

IF NOT R THEN LET X=URL B

160

NEXT I

530

170

LET X=K

540

LET B = WL BS

180

SLOU

550

GOTO

URL "60"

190

FOR I=NOT PI TO CODE

"Z" lea*

REM SIN X,0,2*PI

.COS x,e,2*

IN <2*X) +SI

sea

PLOT I, URL "43"* (URL

R*-L> - BI.TBN X.-

•1,1, SIN XtS

;h-[_)

N 13lX) ,e

4*PI,RSN X,

-1, 1,LN X, .

a 10

LET X=X*DX

1,8.7, EXP

X, -1, l.MOO
.1,2, EXP - (

(X-INT X-.5

£20

NEXT I

) ,a,3, l/'X,

X*X> , -2,2 .

lower and upper limit. If you only have
IK RAM then you will not be able to
use this feature. If this is the case, then
enter the program without the USR
routines in memory and omit lines 10,
20, 25, 35, 45, 80, 230, 300, and every
line above 300.

You cannot plot more than one func-
tion on the screen at the same time, but

September/October 1983 <= SYNC

none of the prompt messages will appear
after the first graph. Prompt messages
also do not appear on the 1 K version de-
scribed above.

I hope that these routines and pro-
grams are of use to you. If you have
other ideas on how to extend the
capabilities of this little computer in this
way, drop a line to SYNC. H

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2KRAM

Quick-draw! Harry Doakes

More than two years ago, Sinclair an-
nounced that the 4K ROM of the ZX80
would be expanded to an 8K ROM and
that one of the new commands would be
DRAW. DRAW was just what it sounded
like— a command to draw a line on the
TV screen.

But DRAW never came to be. Even an
8K ROM has only so much room, and
DRAW would not quite fit. There is a
routine to do the same thing in the ZX81
and TS100Q manuals— but it is in Basic,
and it is slow.

If you have been following this series
of articles on programming in machine
code, you have already learned how to
translate many Basic commands into ma-
chine code. This time, we will look at two
new instructions, and then see how they
can be used in the machine code trans-
lation of that line-drawing routine. We
will also look at numbers in base 16— the
mysterious "hex" numbers— and see why
they are handy for machine code pro-
gramming.

Negative Thinking

You already know that each regular
register in the Z80 microprocessor, like
each byte of memory, can hold any num-
ber between and 255. Sometimes,
though, we want to keep track of a nega-
tive number— a number that is less than
zero.

Fortunately, there is an easy way to do
it. Suppose register A contains the num-
ber 255— the highest number it can hold.
Now suppose the next instruction in the
Z80 program is

INC A
In Basic, this would be

LETA=A+1

Harry Doakes, PO Box 10860, Chicago. IL 60610.
90

lost machine code listings are in hex;
hex numbers save space each
has exactly two digits.

What is the number in register A now?
It is zero. When a register goes "over the
top," it starts all over again at the bottom.
It is as if the register automatically sub-
tracts 256 if a number is too high. In
other words, when you are using a regular
register, 255 +1=0

As you might guess, subtraction works
the same way. Once a register hits bottom,
it starts over again at the top. In this case,
it is as if the register automatically adds
256. Thus, - 1 = 255. But that does not
help much— or does it?

It turns out that you really can use 255
instead of -1. Surprising as it sounds, all
the arithmetic works. Consider this
example:

14+(-l)=13
Can we really replace -1 with 255? Here is
how it works:

14+255=269
Since 269 is higher than 255, the register
automatically subtracts 256:
14+255=269-256=13

The arithmetic does work— and that
can be a big advantage, as long as we
keep track of whether the value in a byte
or register is a regular number (between
and 255) or a negative number.

More Negative Thinking

Now that we have negative numbers,
we can use an instruction that makes a
number negative. The instruction

NEG
will take whatever value is in register A
and make it negative. The equivalent in

Basic might be
LET A=-A

That probably seems pretty straight-
forward—but there is a catch. Remember,
we have to keep track of which numbers
may be negative. For example, if the value
in register A is 1 , NEG will change it to -1 ,
or 255. But, if the number in A is 255,
NEG will not make it -255. NEG assumes
255 really means -1, so it changes the
value to 1.

If this sounds complicated, here is a
simple rule: When you are using negative
numbers, figure that only the values from
to 127 are positive. The other values
are negative numbers— from -1 down to -
128. That way, you are not likely to lose
track of what is negative and what is not.

Great Divide

The Z80 processor can add and sub-
tract pretty well, but it has a tougher time
multiplying and dividing. It can do one
kind of division, though: it can divide by
2. (Maybe that does not seem so great—
but it is better than nothing at all.)

The instructions that divide by 2 are
called "shift" instructions. Here is why:
suppose you divide 142 by 10. The answer
is 14.2— which looks a lot like 142. The
difference is that the answer has been
shifted over one decimal place. The Z80
shift instructions do the same sort of thing,
but using base 2 instead of base 10. Divi-
ding by 2 shifts a number over one
"binary" place.

Fortunately, we do not have to worry

September/October 1983 c SYNC

much about what a "binary" place might
be. When you divide by 2, the answer is
the same in binary or in decimal.

There are two different divide-by-2 in-
structions—one for numbers you know
are positive (0 to 255) and one for num-
bers that might be negative (-128 to 127).

The first is the "shift to the right
logically" instruction, abbreviated SRL.
For this instruction, the Z80 assumes that
the value in the register is a positive
number and divides it by 2. For example,
suppose register B contains 15. After the
instruction
SRLB
register B will have the value 7— which is
the next whole number less than 15/2.

For numbers that might be negative,
you can use the "shift to the right arith-
metically" instruction. If B is -15, then
after

SRAB
This will equal -8, which is the next whole
number less than -15/2.

Notice that it is always the next number
lower, not closer to zero. It is exactly the
same as the INT function in 8K Basic,
though not the same as integer arithmetic
in 4K Basic.

Why is one kind of shift called "logi-
cally" and the other "arithmetically'? It is
jargon, that is all— and it is only
mentioned here because those initials are
used in the abbreviations SRL and SRA.

You can use these "divide-by-2" in-
structions with any of the regular regis-
ters: A, B, C, D, E, H, or L. You can also
use register pair HL as a pointer, with the
instructions

SRL (HL)
and

SRA (HL)

Doubling Up

If you can "shift to the right" to divide,
can you "shift to the left" to multiply?
Certainly. If register D equals 45, then
after

SLAD
D will equal 90. The SLA instruction
works with all the regular registers, and
with positive or negative numbers. But
remember, you may get something you
do not expect if the result is outside the
right range.

Drawing the Line

Now let's look at the routine that draws
a line. Listing 1 is a slightly modified
version of a program in the "Graphics"
chapter of the ZX81 or TS1000 manual.

It is designed to work as a subroutine
in Basic. To draw a line from one point
on the screen to another, you use LET
statements to make XSTART and
YSTART equal the starting coordinates
of the line, and XEND and YEND the
ending coordinates; then you simply

September/October 1 983 « SYNC

1 000

LET U=XEND-XSTART

1010

LET M=ABS(U>

1 020

LET X1=SGN(U)

1030

LET X2=X1

1 040

LET v=YEND-YSTART

1 050

LET N=ABS(v>

1060

LET Yl=SGN(v)

1070

LET Y2=Y1

1 080

IF MsN THEN GOTO 1140

1 090

LET U=N

1 1 00

LET N=M

1110

LET M=U

1120

LET X2=0

1 1 30

GOTO 1150

1 1 40

LET Y2=0

1150

LET S=INT(M/2)

1160

FOR 1=0 TO M

1170

PRINT AT YSTART. XSTART; CHR«

(128)

;

1180

LET S=S+N

1190

LET XQ=X2

1 200

LET YQ=Y2

1210

IF S<M THEN GOTO 1250

1220

LET S=S-M

1 230

LET X0=X1

1240

LET YQ=Y1

1250

LET XSTART=XSTART+XQ

1260

LET YSTART=YSTART+YO

1270

NEXT I

1280

LET XSTART=XEND

1290

LET YSTART=YEND

1 300

RETURN

GOSUB 1000. When it is finished drawing,
the old ending coordinates become the

new starting coordinates.

For example, to draw a triangle whose
three corners are at coordinates (1,2),
(3,8), and (10,5), you could do this:

10LETXSTART=1
20 LET YSTART=2
30 LET XEND =3
40 LET YEND=8
50 GOSUB 1000
60LETXEND=10
70LETYEND=5
80 GOSUB 1000
90LETXEND=1
100LETYEND=2
110 GOSUB 1000

If you have the 4K ROM, you will not
be able to run the Basic program. There
is no PRINT AT command in integer
Basic. And, if you have only lK RAM,
you probably will not have enough
memory. That is because the display file,
where the picture sent to your TV screen
is stored, can take up as much as 729
bytes— nearly 3/4K.

Parlez-vous Z80?

Translating the line-drawing routine
into Z80 machine code is generally pretty
straightforward. Figure 1 shows the trans-
lation for a computer with 2K RAM. For

Figure 1. Basic and Machine Code Versions of Listing 1.

1000 LET

U=XEND

-XSTART

3A F4 47

LD A, (XSTART)

; start by subtracting
XEND-XSTART

LD B,A

3A F6 47

LD A, (XEND)

SUB A,B

;now A=U; the flags are set

1010 LET

M=ABS(U)

1020 LET

X1=SGN(U)

1030 LET

X2=X1

16 01

LD D, 1

;D=X1=SGN(U) ;
suppose it is a plus..

30 04

JR NC.PLUS1

;if A-B is positive, then M=A,
Xl = l

ED 44

NEG

; i f it is negative, M=-A. . .

16 FF

LD D.-l

; ... and Xl=-1

20 02

PLUS1:

JR NZ.SKIP1

1 -finally, if A-B=0. . .

16 00

LD D,0

; . . .then X1=0

SKIP1:

LD H,A

;now H=M; D=X1 (and X2>

LD A,D

; 1 et ' s store XI now

32 FA 47

LD ( X 1 > , A

1040 LET

V=YEND

-YSTART

3A F5 47

LD A, (YSTART)

snow do the same thing, except

LD B,A

;with L=N; E=Y1 (and Y2)

3A F7 47

LD A, (YEND)

SUB A,B

1050 LET

N=ABS(V)

1060 LET

Y1=SGN(V>

1070 LET

Y2=Y1

IE 01

LD E, 1

30 04

JR NC.PLUS2

ED 44

NEG

most program lines each Basic statement
becomes a short series of machine code
instructions. The most complicated of
them is the machine code version of
PRINT AT.

But at the very beginning, you will see
ABS and SGN, a pair of Basic functions
we have not translated into machine code
before. Let's take a quick look at how our
machine code version of ABS and SGN
works.

ABS is the absolute value function in
Basic. Simply put, it means this:
If X is positive, then ABS(X)=X
If X is negative, then ABS(X)=-X
If X is zero, then ABS(X)=0
In other words, you could replace line
1010 in the Basic program with
1010 IF U>0 THEN LET M=U
1012 IF U<0 THEN LET M=-U
1014 IF U=0 THEN LET M=0
SGN is the sign function:
If X is positive, SGN(X)=1
If X is negative, SGN(X)=-1
If X is zero, SGN(X)=0
You could replace line 1020 in the Basic
program with

1020 IF U>0 THEN LET Xl = l
1022 IF U<0 THEN LET Xl=-1
1024 IF U=0 THEN LET XI =0
You can see that ABS and SGN work
in much the same way. That is why, to
shorten our machine code a little bit, we
have combined the two functions into
one short routine. Here is how it would
look in Basic:
1010 LET XI = 1

1012 IF U > =0 THEN GOTO 1018
1014 LET U=-U
1016 LET XI =-1

1018 IF U<> THEN GOTO 1022
1020 LET X 1=0
1022 LET M=U

In machine code, it works like this:
When we subtract XSTART from
XEND, the zero flag and the carry flag
are either sent up or down. Remember,
the zero flag goes up if the result equals
zero, and the carry flag goes up if the
result of a subtraction is less than zero;
otherwise, the flags come down. By
checking the flags, we can tell whether
the number is positive, negative, or equal
to zero.

We start with a guess— maybe the num-
ber is positive. The sign will go in register
D, so we say

LDD.l
Next, we test our guess. If U is negative,
the carry flag is up. Thus, we say

JR NC.PLUSl
that is, jump ahead if it is not negative.
PLUS1 is just a dummy name; we will
have to figure out later how far the jump
really is.
If U is negative, we say
NEG
LDD.-l
That changes the negative number in A

Figure 1. Continued.

IE FF LD E,-l

20 02 PLUS2: JR NZ,SKIP2

IE 00 LD E,0

6F SKIP2: LD L,A

7B LD A,E

32 FB 47 LD <Y1) ,A

1080 IF M>N THEN GOTO 1140

LD A,L

CP H

38 06

JR CMHIGH

;now L=N and E=Y1 (and Y2)
; let's store Yl now

; compare It and N

; i -f M is higher, jump

1090 LET U=N
1100 LET N=M
1110 LET M=U
1120 LET X2=0
1130 GOTO 1150

6C NHIGH: LD L,H
67 LD H,A

lib 00 LD D,0

18 02 JR SKIP"

; otherwise, swap M and N

; remember, N was already in A

:D=X2

1140 LET Y2=0

IE 00 MHIGH: LD E.O

; i-f M>N then do this; E=Y2

1150 LET S=INT<M/2)

32 FC

32 FD 47

32 F9

32 FE 47

SKIP3: LD A, D

inow store the variables

F8 47
2F

LD <X2),A

LD A,E

LD (Y2),A

LD A,L

LD (N),A
A,H
(M) ,A

3RA A

LD <S),A

LD
LD

iS=M/2

1160 FOR 1=0 TO M

3E 00
32 FF 47

LD A,0
LD < I ) , A

; start I with

1170 PRINT AT YSTART, XSTART;CHR*< 128) ;

2A 0C 40 PLOT:

3A F4 47

FE 20

30 14

16 00

3A F5

FE 16

30 09

06 21

20 FC

36 80

LOOP 1 1

LD HL, (16396)

INC HL

LD A, (XSTART)

CP 32

JR NC.BUMP

LD E,A

LD D,0

ADD HL,DE

LD A, (YSTART)

CP 22

JR NC.BUMP

LD E,A

LD B,33

ADD HL.DE

DEC B

JR NZ,L00P1

LD (HL),128

;start o-f the display -file

; posit ion is 0,0

;i-f XSTART>31, do not plot it

;DE=XSTART

;position is XSTART,

;if YSTART>21, do not plot it

;DE=YSTART

; there are 33 bytes per line

;add YSTART bytes

;do it 33 times

;plot position XSTART, YSTART

1180 LET S=S+N

3A F9 47 BUMP:

3A FE 47

32 FE 47

LD A, (N>
LD B,A
LD A, (S)
ADD ft,B
LD (S),A
LD C,A

; add S+N

;store S

;C=S

September/October 1983 « SYNC

1190 LET

XQ=

=X2

1200 LET

YQ=

=Y2

3A FC 47

LD A, <X2)

LD D,A

;D=XQ

3A FD 47

LD A, (Y2>

LD E,A

;E=YQ

3A F8 47

LD A, <M>

LD B,A

;B=M

1210 IF S<M THEN GOTO 1250
79 LD A,C

B8
38 OC

CP B

JR C,SKIP4

; compare M and S
(registers B and C)

;if S<M then jump

1220 LET S=S-M

32 FE 47

SUB B
LD (S),A

; otherwise, subtract.
; . . . store S. . .

1230 LET XQ=X1
1240 LET YQ=Y1

3A FA 47

3A FB 47

LD A, (XI)
LD D,A
LD A, (YD
LD E,A

; . . .replace X2 with XI,
; . . .and Y2 with Yl

1250 LET XSTART=XSTART+XQ

3A F4 47 SKIP4: LD A, (XSTART) ; add

82 ADD D

32 F4 47 LD (XSTART), A ; store XSTART

1260 LET YSTART=YSTART+YQ

3A F5 47

32 F5 47

l_U M , \ T 3 I f-ir\ | J i ouu

ADD E

LD (YSTART),A ; store YSTART

1270 NEXT I

LD A, <I)

INC A

LD (I), A

LD B,A

LD A, <M)

CP B

JR NC,PL0T

; add 1 to I . . .

; store I

;M is the limit

;i-f KM then plot again

1280 LET XSTART=XEND

3A Ft 47
32 F4 47

LD A, (XEND) ;otherwise, update XSTART.
LD (XSTART), A

1290 LET YSTART=YEND

5ft F7 47

52 F5 47

LD A, (YEND)
LD (YSTART), A

.update YSTART.

1300 RETURN

RET

, and that' s i t !

Decimal

He*

18420

47F4

18421

47F5

18422

47F6

18423

47F7

18424

47F8

18425

47F9

Variable

XSTART

18426

47FA

YSTART

18427

47FB

XEND

18428

47FC

YEND

18429

47FD

18430

47FE

18431

47FF

September/October 1983 « SYNC

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to a positive value, and makes the sign -1.

Now we are OK if the number is posi-
tive or negative. But what if it is zero?
The zero flag still tells us whether the
result of our subtraction was zero or not.
If it is up, we will need to change the sign
(in register D) to zero:

PLUS1: JRNZ.SKIP1

LDD,0

Finally, we will put our absolute value
in register H for safekeeping:

SKIP1:LDH,A
When we are finished, the sign is in regi-
ster D and the absolute value is in register
H.

As usual, translating from Basic to ma-
chine code is not really very complicated.
Just break the routine down into simple
steps— steps that can be performed by
something as simple-minded as the Z80
processor— and you are off and running.

Off and Running . . . Almost

When you first looked at Figure 1 , you
may have noticed a few other things. This
is easily the longest machine code routine
we have tried— 200 bytes long, in fact.
And in the far left-hand column, where
we would normally put each instruction
in numerical codes— the version of the
program the computer understands-there
is a mixture of numbers and letters. What
goes on here?

Because this routine is 200 bytes, it is
not practical to POKE in the whole pro-
gram each time you run it. To get around
that problem, we will get the computer to
do the work. The program in Listing 3
expects its first line to be a REM state-
ment containing the numerical version of
a machine language program. It converts
the characters in the REM line into values
between and 255, and then POKEs them
into memory starting at location START.

But instead of decimal numbers, this
time the numerical codes are in base 16,
or hexadecimal numbers— "hex" numbers
for short.

Putting on the Hex

There is a chapter in your ZX81 or
TS1000 manual that tells something about
hex numbers— it is titled either "Count-
ing" or "Number Systems," depending on
which edition you have. It explains how
hexadecimal numbers use all the digits
from through 9, and the letters A, B, C,
D, E, and F as well. If you have not
looked at it before, be sure to read it.

But even more important for machine
code programming is the "Character Set"
appendix. It has all the machine code
instructions, along with both the decimal
and hex numbers the Z80 processor
understands. That makes it very easy to
translate a number between decimal and
hex— you can just look in the appendix.

Why use hex numbers this time? To

save space. Notice that every hex number
up to FF (in decimal, 255) can be written
with exactly two digits. That means each
pair of digits is one number. You can

Listing 2

8KROM

10 PRINT "HOW MANY BYTES?"
20 INPUT A

30 LET RT-PEEK 16388+256*PEEK
16389

40 LET RT=RT-A

50 LET 1-1= I NT (RT/256)

60 LET L=RT-256*H

70 POKE 16388, L

80 POKE 16389, H

90 NEW

4KROM

10 PRINT "HOW MANY BYTES'' "

20 INPUT A

30 PRINT "HOW MANY K OF RAM DO
YOU HAVE?"

40 INPUT RT

50 LET RT=1024*(RT+16)-A

60 LET H=RT/256

70 LET L=RT-256*H

80 POKE 16428,49

90 POKE 16429, L
100 POKE 16430, H
110 POKE 16431, 195
120 POKE 16432, 108
130 POKE 16433,2

140 PRINT "YOUR ROUTINE WILL ST
ART AT ";RT

150 PRINT "PRESS NEWLINE TO RES
ERVE SPACE"
160 INPUT A*
170 LET A=USR( 16428)

cram them together with no space be-
tween, and then easily break them up
into pairs again. For example, it is easy to
see that

210000C9
means the same thing as

21 00 00 C9

You cannot do that with decimal num-
bers. Some decimal numbers have one
digit, some two, and some three. Suppose
you left the spaces out of this sequence:

6 173 22 2 201
If you did not already know what the

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September/October 1983 ® SYNC

original numbers were, you would never
be able to re-create the original sequence
from

6173222201

Of course, you could use zeroes to
make each number three digits:

006173022002201
But then our 200-byte routine would fill
up a REM line 600 bytes long. That is a
lot of memory to take up if you only have
2K. With two-digit hex numbers, it only
takes 400 bytes, or two-thirds the space.

There is another advantage to using
hex numbers. Most machine code listings

Listing 3.

1 REM 3AF447473AF64790 160 1300
4ED4416FF20021600677A32FA473AF54
7473AF74790 1 EO 1 3004ED44 1 EFF2002 1
E006F7B32FB477DBC38066C67 1 6001 80
2 1 E007A32FC47 7R3'?Fr>477n3'?F<v477r?

2FB47CB2F32FE473E0032FF472A0C402
33AF447FE2030 1 45F 1 600 1 93AF547FE 1
630095F062 1 1 90520FC36803AF947473
AFE478032FE474F3AFC47573AFD475F3
AF8474779B8380C9032FE473AFA47573
AFB475F3AF4478232F4473AF5478332F
5473AFF473C32FF47473AF847B8309D3
AF64732F4473AF74732F547C9

10 LET RSTART=16514

20 LET START=PEEK 16388+256*PE
EK 16389

30 LET A=0

40 LET H=PEEK (RSTART+2»A) -28

50 IF H<0 OR H>15 THEN STOP

60 LET L=PEEK (RSTART+2*A+1 > -2
8

70 IF L<0 OR L 15 THEN STOP

80 LET N=16*H+L

90 POKE START+A.N
100 LET A=A+1
110 GOTO 40

16K RAM Changes

1 REM 3AF47F473AF67F90 160 1300
4ED44 1 6FF2002 1 600677A32FA7F3AF57
F473AF77F901E013004ED441EFF20021
E006F7B32FB7F7DBC38066C67 1 600 1 80
2 1 E007 A32FC7F7B32FD7F7D32F97F7C3
2F87FCB2F32FE7F3E0032FF7F2A0C402
33AF47FFE2030 1 45F 1 600 1 93AF57FFE 1
630095F062U90520FC36803AF97F473
AFE7F8032FE7F4F3AFC7F573AFD7F5F3
AF87F4779B8380C9032FE7F3AFA7F573
AFB7F5F3AF47F8232F47F3AF57F8332F
57F3AFF7F3C32FF7F473AF87FB8309D3
AF67F32F47F3AF77F32F57FC9

4K ROM Changes

10 LET RSTART= 16427

20 PRINT "START LOCATION?"

25 INPUT START

in magazines and in many of the books on
machine code programming are in hex
numbers rather than decimal. So once
you have the hang of hex, it is much
easier to understand those books and
articles— and use the machine code pro-
grams they describe.

Quick Draw

To use this machine code line-drawing
routine, very carefully type in the pro-
gram in Listing 3. (It is designed for an 8K
ROM computer with 2K RAM; be sure to

September/October 1983 <= SYNC

use the alternate REM line if your com-
puter has 16K.) Count the number of
characters in the REM line after you have
typed it in, to make sure you have not
missed any— or better still, check the
whole line to make sure it is right.

Now— before you try the program—
SAVE it on tape! If you have made a
mistake, you will be able to edit just the
REM line to correct it, instead of typing
the entire program again.

Next, use the program in Listing 2 to
save space at the top of memory. For this
routine, you should save 212 bytes: 200
for the program, and 12 for the variables.

Listing 4.

LET Q=PEEK 16388+256*PEEK

6389

FOR A=l TO 22*32

PRINT " ";

NEXT A

INPUT XSTART

POKE D+200, XSTART

INPUT YSTART

POKE Q+201, YSTART

INPUT XEND

100

POKE Q+202, XEND

110

INPUT YEND

120

POKE Q+203,YEND

130

LET A=USR <Q>

140

GOTO 90

4K ROM Changes

PRINT "START LOCATION''"

INPUT Q

CLS

Then LOAD the program you have
SAVEd on tape, RUN it, then edit out
each of the program lines. Finally, type in
and RUN the program in Listing 4. It
demonstrates the line-drawing routine. If
your computer has SLOW mode, it will
leave no doubt how much faster than
Basic machine code can be.

Coining Attractions

A machine code routine like this one is
fast— but it is also long. Everything the
routine does must be included in the pro-
gram, and sometimes that means "rein-
venting the wheel." After all, there are
already machine code routines for print-
ing on the screen, plotting points, and
many other functions already in your
computer— stored in the ROM.

Next time, we will see how to put those
routines— the "ROM calls"— to work. We
will also learn about writing our own
subroutines, when there is nothing in
ROM that does exactly what we want.
And we will take a look at the "stack,"
and some of the special features of the
Sinclair computers.

If you have comments or questions
about machine code programming, or
something is not quite clear, let me hear
from you. Be sure to send along a stamp-
ed, self-addressed envelope if you need a
reply. V

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User-Friendly
Statistical Program

"SUPER-STATS"

One load cassette gives instructions and easy
statistical use on your 2X81/TS100 with RAMPACK

Routines include:

• Means, standard deviations, standard errors,
variance, confidence limits lor one and two-tail
tests

• Pearson R coefficient ot correlation, with scatter
display

• Zand T tests

• Chi Square (with Yates correction if required)

• Linear Regression, with equation, slope.
v intercept, and optional line plot.

Order Today tor $14 95 Includes Shipping and
Handling (Cluck or MO.) From:

Klnetronici Corp

Lake Bluff. IL 60044

PO Box 411
312 -295- 5600

The ZX Stock Exchange DonaidA. Burgio

You have just inherited $10,000 from a
wealthy uncle who made it big on the
stock market. He also gave you the
modem number of his broker, a
computer.

The ZX Stock Exchange carries stocks
listed on the New York Stock Exchange
as well as stocks not listed there. For the
purpose of demonstrating how the market
works, a random selection of stocks of
five stocks has been made and entered as
three letter abbreviations: AAA, BBB,
CCC, DDD. EEE. When you enter the
program, you may substitute the stocks
that you believe have the greatest opten-
tial. However, you must use designations

Figure 1.

STOCK

A AND A BS50CISTES WVI
B AND B BUYERS BBB

c rno c com. co. ccc

D RND D DEVELOPERS ODD
E RND E ENERGY EEE

ZX STOCK FKCHflNGE (1UER

SYNC:

STOCK ASSET3=* ■>.!_

CB5H ASSETS = * 10000.04

TOTAL ASSETS =» 10000.00

Your broker the computer charges you
a modest one percent brokerage fee on
all transactions made.

Getting Started

First, carefully type in the program in
Listing 1. Save it by typing GOTO 2760.
This will cause it to run automatically
after LOADing.

When the program is running, the first
thing the computer will ask is whether or
not you want instructions. Regardless of
whether you get instructions, press S to
begin.

Figure 1 shows the initial printing of
the stock: the name, initials, price per

Figure 2

♦«« END Of TRADING: DRY

STK. t-SHR. HDS. • URLUE

L •*•

CHRHOE

o.ee -7.85

537S . OO -5 . 75

e . eo - 6 . s

o . oo -* . as

RRR 116.88 •
BBB 78 . 75 O
CCC 187.58 SO

ddd 7a . ao e

EEE 104 . as B
EEE SPLITS STOCK.

ZX STOCK EXCHANGE RUER.:5
NET CHANGE: -6.55

STOCK ASSETS-* 5375.88
CRSH ASSETS* % *a88.87

TOTAL A55ETS=* 9S5S.ee

price per share, your holdings (the num-
ber of shares in your portfolio), the total
value of the stocks, and the change from
the previous day. The next lines will be
any messages, the ZX Stock Exchange
average, the net change, and the value of
your stock, cash, and total assets. You
will then be asked whether you want to
continue. Type Y for yes and N for no.

Program Description

Lines 10-120 and 230-830 initialize the
program and give instructions if re-
quested.

The subroutine in lines 130-220 is fre-
quently used for formatting. A cash value

Figure 3

*** END OF TRADING: DAY Z #*#
STK. »/5HR. HDS. * URLUE CHANGE 1

AAA 107 . 35

BBB 76 . as

CCC 183.75 ae

DDD 69.25 O

EEE 97 . 80 8

B . 00 -6.75

0.00 -a. 5

ae75 . ee -3 . 75

0.0a -a. 75

. 00 -7 . as

IS YOUR TRANSACTION IN:

of three letters. You must also put in the
full name of each in lines 890, 920, 950,
980, and 1010.

The stock prices are generated some-
what randomly, but they show short and
long term trends just as on other stock
exchanges. To get the "feel" of the mar-
ket, the program should be played for at
least 10 market days.

Donald A. Burgio, 20 Oak Rd.. Congers. NY
10920.

share. Your stock, cash, and total assets
will then be briefly shown.

Next the computer will ask you for
your transaction for each stock. To buy,
type xxx, where xxx is the number of
shares you want to buy. If you do not
want to buy or sell, type 0.

After you have entered your initial
transactions, the screen format will look
like Figure 2. At the top will be displayed
how many days you have been playing.
Then a chart will show the stock initials,

such as 23.6 is inputted as G. The subrou-
tine will then manipulate G so that it
comes out as a neater form stored in R$,
23.60 in the example. The length of R$ is
stored in L for neatness by lining up the
decimal points on the cash amounts.

Line 190 takes care of a peculiar hap-
pening on the ZX81 which is due to the
nature of floating point arithmetic. E.g.,
type PRINT 1012.56-INT 1012.56 or
PRINT 1012.56-1012. The computer
should print .56, but instead it prints

September/October 1983 e SYNC

0.55999994. This happens with a few other
numbers also, and it must be accounted
for in software.

Lines 840-1010 set up the initial display
shown in Figure 1. Lines 1012-1 180 calcu-
late the stock exchange average (EA) and
net change (NO. Lines 1190-1320 print
your stock assets (SA), cash assets (C),
and total assets (D).

Listing 1. The ZX Slock Exchange

IB REM oTOCK MRRKET SIMULITIOI-i

ES REM EY V- - BURGIO/2B

OBK RORD •CONGERS , MY 1O920

3d DIM I*(5,3)

*a DIM OS (2)

50 LETT 0* = 'XNT (SHD»i.99) «1"

68 LET I*<l)="ORR"

7« LET I* (2) ="BBB"

SB LET I* (3) ="CCC"

90 LET It (4.) ="DDD"

100 LET I*(S)="EEE"

110 RRND

120 GOTO 230

130 LET X=RBS G

14.13 LET B = INT X

1S0 LET E=X-B

160 LET Z*=STR« B

170 IF E=0 THEN LETT O* = "00"

180 IF E<>0 THEN LETT 0*=STR» 11.

ee<Ei

ISO IF 0*(2)="." THEN LET C*=ST
Rt ( (1O00*E) +.01)

200 LET R$=ZS+" . "+0*

210 LET L=LEN R$

220 RETURN

230 LETT R = INT < (RND/1B) 1 100+ . 5)
/10O

24.0 DIM 5(5)

2S0 DIM P(5)

260 DIM T (S)

270 DIM CI5)

2SB LET TT=0

290 LET F=0

300 LET D1=B

310 LET D2=0

320 LET P=0

330 LET P2=0

34.0 LET DY=0

350 LET ER=0

360 SLOU

370 CLS

380 FOR 1=1 TO 20

390 £PJL NT -,fi T . ^ e -

400 PRINT RT 8, 0"]
STOCK EXCHANGE "

410 NEXT I

420 PRINT RT 3,0;"UHRT IS YOUR
NOME"?"

430 INPUT N*

440 PRINT RT 3,0, ; "DO YOU URMT I
NSTRUCTIONS-? IY^N) "

450 INPUT ZC

460 IF Z»="N" THEN PRINT RT 3,0

470 IF Z*="N" THEN GOTO 660

480 CLS

490 PRINT "WELCOME TO THE ZX ST
OCK EXCHRNGE"

SO0 PRINT TRB ( 133-LEN N*)^2);N
* + " . '•

510 PRINT "YOUR ACCOUNT CURRENT
LY CONTAINS"

520 PRINT "* 10,000. YOU MRY BU
Y OR SELL"

530 PRINT
RURILRBLE "

540 PRINT "STOCK. THEIR PRICES,

RND THE"

5SO PRINT "NUMBER OF SHRRES IN
YOUR PORT-"

560 PRINT "FOLIO UILL BE PRINTE
E>. FOLLOU-"

570 PRINT "INS THIS THE IMTITIR
L S OF EACH"

5S0 PRINT "STOCK UILL BE PRINTE
t>. HERE YOU"

590 PRINT " INDICATE R TRRNSRCTI
ON. TO BUY"

600 PRINT "A STOCK TYPE XXX, UH
ERE XXX IS

610 PRINT "THE NUMBER OF SHRRES

YOU UISH TO"

620 PRINT "BUY. TO SELL TYPE -
XXX . UHERE"

630 PRINT "-XXX IS THE NUMBER O
F SHRRES YOU"

640 PRINT "UISH TO SELL. RIP
ERCENT SRO-"

KERRGE FEE UILL RUTC
KRT"

66B PR IN HRRGED TO YOUR R

ccoui

670 PRINT TRB 11: "GOOD LUCK."

IB LET S ( 1) =130

690 LET S (2) -9B

700 LET S t3) -120

710 LET S 14> =85

720 LET S (SJ = 115

730 LET TR=V»RL A*

740 PRINT AT 21,7; "PRESS S

750 - IF INKEY»«"S" THEN EOT!
768 PRINT

STOCKS.

fl TRBLE OF

77S PRINT RT 0,0: "UELCOME TO Tf

EC ZX STOCK EXCHRNGE"

7B0 GOTO 750

790 IF RND>.5 THEN. GOTO 810

Continued

September/October 1983 e SYNC

(JKe fc-mb's-

"BAC-TRAC"

A "PACMAN" STYLE PACKAGE OF
FUN. 54 GAME VARIATIONS.

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Cassette: $6. Listing: $2.

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1469AALBORGWAY

SOL VANG, CA 93463

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W • • miiiiiiiiiii mini

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.Listing I. Continued.

880 LET R=-R

eie ci_s

ese gosub 2010

63BI LETT = 10300

BAB PRINT

850 PRINT "STOCK

NT. «/SHRRE"

860 PRINT "

870

LETT G=S(1)

eee

GOSUB 130

890

PRINT "A RND R

PR ••

TRB (3S-L) ; R*

900

LET G=S(2>

910

GOSUB 130

920

PRINT "B RND B

BB "

TAB (32-L) , R*

930

LET G=S<3>

940

GOSUB 130

950

PRINT "C RND C

CC "

TAB (32-L) ; R*

960

LET G=S(*)

970

GOSUB 130

9B0

PRINT "D RND D

DO -

TAB (32-L) , R*

990

LET G=StS>

1000

GOSUB 130

1010

PRINT "E RND E

EE "

TRB (32-L) ; R»

ASSOCIATES R

CORL CO.

PEUELOPERS D

ENERGY

1020 LET TRsER

1030 LET ER=0

1040 LET SA=B

1050 FOR 1=1 TO 5

1060 LET ER=ER+S(I>

1078 LET SR=Sfl+S (I) *P(I)

1080 NEXT I

1090 LET ER=INT < 108* (ER/S) + . 31 •

188

1100 LET NC=INT ( (EA-TR) »100+.S>

/IBB

1110 LET D=SR+C

1120 IF F THEN (SOTO 1160

1130 PRINT

114.0 PRINT "ZX STOCK EXCHRNGE RU

ER. : ";ER

1158 GOTO 1190

1160 PRINT

1170 PRINT 'ZX STOCK EXCHRNGE RU

ER . : " ; ER

1188 PRINT

1190 PRINT

1200 PRINT N*; " : "

1210 LET SR=INT (lBBtSRt.Sl/IBB

1220 LET G=SR

1230 GOSUB 130

124.0 PRINT "STOCK ASSETS = *" , TRB

(21-Ll ; R»

1250 LET C = INT lieatCt.Sl .'IBB

1268 LET G=C

1270 GOSUB 130

12S0 PRINT "CASH ASSETS= *";TAB

(24. -L) ; R*

1298 LET D = INT < 100*D+ . 5) /10B

1320 LET G=D

1310 GOSUB 130

1323 PRINT "T3TRL RSSETS = *" , TRE

I2J-L) ;R»

1330 PRINT

1319 IF NOT F THEN PAUSE 225

1358 IF NOT F THEN POKE 164.37,25

13E.81 IF NO! F THEN GOTO 14.00

1375! PRINT "DO YOU UISH TO CONT :■

I-i'-'E" IV •«) "

1330 INPUT C*

1390 IF C*="N" THEN GOTO 2510

1A30 FOR 1-10 tO 21

1410 PRINT AT 1.0; "

NET CHANGE . " , NC

UHAT IS YOUR

1420 NEXT I

1430 PRINT AT 11.
TRANSACTION IN "

1440 FOR 1=1 TO 5

1450 PRINT AT 12 .0, 1$ (I) ; "?■•

14-60 INPUT T ( I)

1470 NEXT I

1480 PRINT AT 20,0; "PLEASE UA IT .

14.90 LET DP = B

1S00 LET CS=0

151B FOR 1=1 TO 5

1528 LET T(I)=INT (T(I>+.5>

1530 IF TCI1 <ee THEN GOTO 1560

1540 LET DP=DP+T (I) *S(I)

1SS0 GOTO 1620

1560 LET DS=DS-T (I> *S (I)

1570 IF -T(I)oPII) THEN GOTO 16
20

1588 PRINT RT 20.0, "YOU HRUE OUE
RSOLD A STOCK; TRY RGRIN.

159B PRUSE 308

16BB POKE 16437,255

1610 GOTO 1400

1620 NEXT I

1638 LET TT=DP+DS

1640 LET BF=INT ( . 1 *TT H00 ♦ . 5) s
100

1650 LET CT=C-DP-BF+DS

1660 IF CT>=0 THEN GOTO 1730

1678 PRINT RT 19,0, "YOU HAUE TR X
ED TO SPEND "

16BB PRINT "•"; -CT; " MORE THRN Y
OU HRUE."

1698 PRUSE 300

1700 POKE 16437,255

1710 GOTO 1400

1720 LET C=CT

1730 FOR 1=1 TO S

1740 LET P (I) =P (I) +T (II

1750 NEXT I

1768 CLS

177B GOSUB S010

1788 LET DY=DY+1

1798 PRINT

DAY " ; DY ;

1600 PRINT

1810 PRINT "STK
ALUE CHANGE"

1820 PRINT "...

**» END OF TRADING:
***"

*/SHR. HDS. • V

1830 FOR 1=1 TO 5

184.0 LET G=S(I>

185B GOSUB 13B

I860 PRINT RT 3H,B; II (I) ; RT 3 + 1

, (ll-L) ; R»; AT 3 + i.i3;P(D;

1870 LET G=S(l)tP(I>

1888 GOSUB 130

1890 PRINT RT 3 ♦ I , (24 -L) ; R»; RT 3

+ 1,26; C (I)

1980 NEXT I

1910 LET F=l

1920 PRINT

1930 LET R=URL ( (STR* RND) (1 TO

4.) >

1940 LET I=INT (RND*7)

194S IF I>5 THEN GOTO 1940

19S8 IF 1=0 THEN GOTO 1940

I960 IF R < . 15 THEN PRINT I*(I>;"

DECLARES DIUIDENTS OF *", (R*4.+ .
5) ; "/SHARE. "

1970 IF R<.1S THEN LET C=C+P(I>*
(R1-4.+ .5)
1988 IF R>.93 THEN PRINT I» ( I) ; "

SPLITS STOCK."
1998 IF R>.93 THEN LET P ( I ) =P ( I )
• 2

2000 GOTO 1020
2010 FAST

2020 IF D1>0 THEN GOTO 2860
2030 LET S=UAL R$
2040 LET D1=UAL A*
2850 LET P=l

2B6B IF D2>0 THEN GOTO 21BB
2078 LET S2=UAL A*
2BSB LET D2=UAL AS
2890 LET P2=l
2108 LET Dl-Bl-1
2110 LET D2=D2-1
2120 FOR 1=1 TO 5
2130 LET R=RNt>

2140 IF R>.25 THEN GOTO 2170
2150 LET R=.25
2168 GOTO 224.0

2170 IF R>.S THEN GOTO 2200
BIBB LET R=.5
2190 GOTO 224.0

2200 IF R>.75 THEN GOTO 2230
2218 LET R=.75
2220 GOTO 2240
2230 LET R=0
2240 LET BC=0

2250 IF P<1 THEN GOTO 2290
2260 IF INT (S+.5)<>INT (I+.5) T
HEN GOTO 2290
3278 LET EC -4
2280 LET P=0

2298 IF P2<1 THEN GOTO 2330
2300 IF INT (S2+.5J<>INT (I+.5)
THEN GOTO 2330
2310 LET BC=-4
2320 LET P2=0
2330 LET C(I)=INT (R»S ( I) ) +R+INT

(3-6#RND+ .5) +BC
234-0 LET C(I)=INT (lBBtCdl ».S) /
180

2350 LET S <I> -S ( I) +C (I)
2360 IF St I) >B THEN GOTO 3400
237B LET C (I) =0
238B LET 5(1) =0
3390 GOTO 3410

2400 LET S(I)=INT ( lBBfS ( I) +.5) '
100

2410 NEXT I
2430 LET TR=TR-1

24.30 IF TR<1 THEN GOSUB 2460
244.0 SLOU
3450 RETURN
3460 LET TR-UAL A*

3470 LET A = INT (IRND/IBI J1B8+.5I
/IBB

248B IF RND<=.S THEN GOTO 2500
2490 LET A=-A
2S00 RETURN
3510 CLS
252 PRINT
2530 PRINT
2S40 PRINT "AT THE END OF ";DY;"

DAYS TRADING: "
255B IF D> =10000 THEN GOTO 2618
2560 PRINT "YOU HRUE LOST J";
2570 LET G=1BBBB-D
25B0 GOSUB 130
3590 PRINT R>
2600 GOTO 2650

2610 PRINT "YOU HRUE MADE »";
3620 LET G=D-1000B
2638 GOSUB 13B
264.0 PRINT Rt

2650 PRINT "ON THE ZX STOCK EXCH
ANGE. "
2660 PRINT

2670 PRINT "HOPE YOU HAD FUN, " ;
N*; "."

2680 PRINT "COME BACK AGAIN."
2690 PRINT RT 20,3; "PRESS S TO R
ETURN TO BASIC."

8730 IF INKEY*="S" THEN STOP

3740 PRINT RT 21 , 0; " ************
*************** *****

2750 GOTO 270B

3760 CLERR

2770 SRUE "STOCK"

3788 RUN

September/October 1983 « SYNC

.Figure 4. List of Variables

Variable

Function

the function INT (RND*4.99)+1

trend slope + sign

formatting: INT X (dollar amount)

big change constant (-4,0,4)

brokerage fee

cash assets

cash total (temporary)

c(D*

change in stock value

total assets

current simulation day

total day's purchases

total day's sales

SPS**

formatting: Cents amount

exchange average

= first simulation day

formatting: initial cash amount

i$(D*

Stock initials

length of R$ (for lining up decimal points)

user ' s name

net change

formatting: the final cents amount

SPS**

P(D*

number of shares in user's portfolio

final formatted cash amount

random value

SPS**

stock assets

SPS**

S(D*

stock values

total assets

total transaction amount

number of days in the trend

T(I)*

transaction amount

formatting: ABS G

formatting: STR$ B, general input

•I

•2 = BBB »4 = DDD

•1 = AAA

•3 = CCC *5 = EEE •• Stock price subroutine: see text.

Lines 1330-1470 ask if you want to
continue. If the answer is Y (yes), the
program then asks you to input your trans-
actions.

Lines 1480-1750 make sure that you
have not spent more than you have and
that you do not try to sell more stock
than you own. The brokerage fee (BF) is
calculated at line 1640.

Lines 1760-2000 set up the screen dis-
play similar to Figure 2. Lines 1940-1990
randomly split stocks (i.e., doubles the
number of shares you presently have) and
declares dividends.

The subroutine that makes the stock
prices is located in lines 2010-2500. Dl
and D2 are random numbers of days
which respectively determine when stock
S will increase 4 points and when stock
S2 will decrease 4 points. If Dl days have
passed, it picks a stock (S), sets P, and
determines a new Dl. This is done simi-
larly with D2, S2, and P2. If Dl or D2
days have not passed, the change is deter-
mined using the trend sign and slope (A),
which is changed after TR days, and a
random amount (R) less than $1.

The conclusion is contained in lines
2510-2750. Lines 2760-2780 save the pro-
gram so that it RUNs automatically after
LOADing.

For the benefit of those who are inter-
ested in programming techniques (and for
those who want to "fix the game to their
advantage," a euphemmistic phrase for
"cheating"), a list of the variables is found
in Figure 4.

Line notes:

390: G (6), THE ZX STOCK
EXCHANGE in inverse, G (5).

400: F (6), THE ZX STOCK EX-
CHANGE in normal letters, F (5).

760: WELCOME TO THE ZX STOCK
EXCHANGE in inverse.

2700 and 2720: Inverse $ (32). V

ZX81

CODE?

NEW ASZMICPLUG - |N

ZX.ASZMIC ROM gives:

• full screen editor

• multiple files

powerful assembler
complete debug
hi-res graphics

ZX.Aszmic Rom replaces the Basic Rom in Timex 1000 and
ZX8 1 /80 computers to transform the machine into a complete
Assembly Language Development station.
Fast. Powerful. Professional. Reliable.

EXTERNAL BOARD

accepts the Aszmic Rom to combine the best of
machine code and basic. 24 I/O lines, Eprom
programmer. 8k user socket.

Aszmic alone, S52 — including comprehensive manual
Aszmic * Board * Manual, only S73
USA dealer enquiries welcome

COMPROCSYS LTD., (S2)
P.O. Box 149, South Croydon,
Surrey, CR2 7YX, England

j Aszmic - manual I enclose S52

^j Board • Aszmic • manual I enclose S73

j Further details I enclose S.A.E or Int. reply coupon

Cheques payable to COMPROCSYS LTD

Name

Address

CIRCLE 13 ON READER SERVICE CARD

Using the Byte-Back Modem Tom Keeney

Introduction

Since buying my Sinclair ZX80, 1 have made so many
changes that it is hardly recognizable. One of the most
satisfying has been the addition of an RS232 interface and a
modem.

I have had a longstanding and probably irrational interest
in data communications. Exchanging data between machines
opens up the prospect of electronic mail and banking. The
individual can also access large data bases such as Compu-
Serve, Dow Jones, and "The Source." I find this an exciting
look at what I hope will be the future.

All that is needed is a device called a modem. It is available
from Radio Shack for about $150. Unfortunately, most
modems will not work on a Sinclair because they require
something called an RS232 interface.

The Byte-Back Modem

When I saw that the Byte-Back Co. was offering a modem
that would attach directly to the Sinclair. I wasted a few
milliseconds in debate and then ordered one. I was even
more pleased when I learned that not only did the system
include an RS232 interface, but that its services were available
to me for other purposes.

The Byte-Back modem is a fine device. It works well and
actually does more than advertised. The instruction manual,
on the other hand, in its attempt to furnish operating instruc-
tions, assembly instructions, and engineering data, is a bit
sketchy. A description of the non-standard output on the
RS232 board is not given nor is there much in the way of
checkout procedures.

This article attempts to provide some of that missing
information as well as to give a review of my experience with
the product. I also recommend V. B. Rice's fine article which
describes his homebrew RS232 interface as a source of
additional information on the subject (SYNC 2:6).

Bytes, Bits, and BAUDs

Before useful information can be exchanged, a common
communications mode must be established to satisfy the
needs of the communications media. This is the function
performed by the modem, its interface, and the associated
software.

First, it is necessary to transform the internal character set
used by the Sinclair into the ASCII character set used by

Tom Keeney, 9629 Dortmund Dr., Huntsville. AL 35803.
100

everyone else. Since the system must both transmit and
receive, this transformation must go both ways. Character
transformation and control of the interface hardware is the
function of the software.

When the data is organized into ASCII codes on the Sinclair
data bus, the data must be communicated to the modem.
This is the function of the interface. An interface is required
because the data on the Sinclair edge connector is arranged
on eight parallel wires while the telephone uses only one.
This means that the computer can operate on eight signals or
bits at once forming a byte. The telephone system, on the
other hand, must take those bits one at a time. It is necessary
to trade space for time by arranging the data bytes into some
agreed upon serial order. It is also necessary for the interface
to control the serial transmission rate or BAUD rate. This
conversion from parallel to serial is old hat for the Sinclair
since that is the method it uses to generate a TV picture and
write to the cassette.

The problem is that the TV and cassette interfaces are
specific to the Sinclair alone and connect only one specific
device. The importance of the RS232 interface board is that
it performs the proper conversion and generates the proper
control functions according to a widely supported industry
standard set by the Electronic Industries Association (EIA).
For the price of a modem alone the Byte-Back system is not
only a modem but also a generalized serial input/output (I/O)
port that will allow the attachment of numerous peripherals
to the Sinclair.

The port operates asynchronously. This means that the
timing between characters is not controlled, while the timing
within a character is. It supports all normal data transmission
rates (as shown in Table 1). It also supports 5 to 8 bit per

Table 1. Clock frequency straps and mode Instruction data bits used to
select the BAUD rate

BAUD rates

Straps

Mode instruction
Data bits

+ 1

-1-16

+64

A
B
C
D

9600
4800
2400
1200

600
300
150

150

37.5

18.75

September/October 1983 « SYNC

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Using

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CIRCLE 9 ON READER SERVICE CARD

Anyone with some electronic assembly experience should
have little trouble although some dexterity is
required as the boards are packed.

directed by an "exception." Since I do not have the resistor
color code down cold and I was not sure I could identify the
rest of the parts, I found myself paging back and forth between
the parts list (where some parts identification information is
given) and the "exceptions" sheet (where additional parts
identification is made). I also found that it helped to check
the components off on the parts list as they were installed.

The assembly presented no surprises, and I was able to put
the kit together in about 6 hours. Anyone with some electronic
assembly experience should have little trouble, although some
dexterity is required as the boards are packed and the traces
are close. I found a 25 watt soldering iron with a .1 inch
grounded tip to be essential. Those with no experience in kit
building whatsoever would probably find the assembled ver-
sion worth the extra cost.

Figure S. Expansion connection.

Printed circuit board -^.K-
V,

Component side

Small connector board

Circuit side

Cut-out

Solder

Finally, the warranty and company attitude should be
mentioned as they are of distinct advantage to the kit builder
and computer hobbyist. The warranty is for the usual 90 days,
but it is unique in that it applies to the kit as far parts and
factory defects are concerned. It does not apply if the kit is
assembled wrong. It remains valid even if you attempt to
repair any malfunction yourself! As an additional aid to the
kit builder, the chief engineer answers the phone on evenings
and weekends when most of us are working on our projects.
As my kit came with a defective chip (which was immediately
replaced), I came to value this service. I found him to be
patient and helpful. Most of the troubleshooting and checkout
hints in this article are his.

The RS232 Board

Assembly of the RS232 board presented few difficulties.
The major point of interest was the expansion plug (Jl on
Figure 1).

Having assembled several kits using the same type of
expansion interface as Byte-Back, I have found it almost
impossible to get a reliable solder joint on the male side of the
connector unless the wire wrap pins are bent as shown in
Figure 5. This is accomplished by grasping the pin with
needle nose pliers, holding the pliers at right angles to the
board and moving the tip parallel to it. The result should be a
pin bent in the shape of a crank as shown. Simply bending the
pins toward the expansion board to form a V with the board
in the middle will not give enough surface area to insure a
secure solder connection as the board is bent and flexed
during installation.

When the RS232 board is completed, it can be checked out
and proper operation verified before connecting the modem.
This requires a minor hardware modification. The following
procedure was developed after conversation with the chief
engineer at Byte-Back and involves getting the board to talk
to itself. This is easy because it operates in full duplex mode
(it can send and receive at the same time) all that is necessary
is to interconnect the pins on J2 as shown on Table 2.

Table 2. Pin assignments lor checkout

Pin Pin Remarks

10 16 Serial data input to

RS232 level translator.

3 9 RS232 transmitter to

RS232 receiver.

8 15 Grounds the clear to

send pin on the 8251A.

The easy way to do this is to build a turnaround plug by
connecting the appropriate pins on a blank 16 pin DIP header
(Jameco # 16pinHP) as shown in Figure 6 then do the follow-
ing:

1) Insert the test plug into J2 and attach the RS232 board to
the Sinclair edge connector.

Figure 6. Turnabout plug.

2) Turn on the Sinclair and look for smoke. Do not worry,
the board is fully buffered and has its own power supply so it
is almost impossible to hurt the Sinclair if a mistake is made
on the RS232 board.

3) If nothing is obviously wrong, key in the program given
in Listing 1 and record it.

Listing 1 . Turnabout test.

10 POKE 39,122 60 IF A =1 THEN GOTO 100

20 POKE 39,23 70 PRINT "FAIL"

30 FOR 1= TO 127 80 STOP

40 POKE 38,1 100 NEXT I

45 PAUSE 2 110 PRINT I

50 LET A = PEEK 38 120 GOTO 30

104

September/October 1983 *> SYNC

Get the most from your SINCLAIR

or Timex Sinclair with these practical books from Syncl

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GETTING ACQUAINTED
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retrieval, education and games. This
practical guide contains scores of fully
documented short routines plus com-
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listing of the ZX81 ROM Monitor.
"Thoughtfully written, detailed, and
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Getting Acquainted With
YourZX81

by Tim Hartnell

This informative volume for the new
ZX81 or Timex Sinclair 1000 user con-
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Checkers, Alien Imploders, Blaster-
mind, Moon Lander, Breakout, Star
Burst and Derby Day. The book also
shows programs for cascading sine
waves, pioiiing graphs and tables, data
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5'/2"x 8", Softbound. #15Y S9.95 ($2.00)

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The Gateway Guide is a practical pro-
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from machine to machine (ZX81 or
Timex Sinclair 1000, 4K ZX80 or 1 K
ZX80) The Gateway Guide describes
each function and statement, illustrates
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5'/2"x8", Softbound. #160 $9.95 ($2.00)

Computers for Kids (Sinclair Edition) by Sally Larsen

This new edition of Computers for Kids is written specifically to introduce
children aged 8 to 13 to the ZX81 or Timex Sinclair 1000. The book
requires no previous knowledge of algebra, variables or computers, and it
enables a youngster to program a Sinclair in less than an hour. There's
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4) Run the program in SLOW mode unless the PAUSE in
line 45 is increased to 10 (this is important if a ZX80 without a
video upgrade is used). In SLOW mode the screen should
flash 128 times then the number 128 should appear, after
which the screen should start to flash again. If the word FAIL
appears at any time, the board is defective and either trouble-
shooting or factory service is in order. The program can be
stopped at any time by pressing the BREAK key. but, if it is
restarted or executed a second time, it should always be with
a RUN 20 or GOTO 20 unless the power has been inter-
rupted.

The first few lines of the program establish the data
communication mode and turn on the board's transmitter
and receiver. The signal timing and error checking system to
be used are also set at this time. The rest of the program
transmits codes from to 127 to the receiver, checks the
receiver output to see if it matches what was transmitted, and
sends the next code if it does. Only 128 codes are sent
because the mode instruction in line 10 established a seven
bit data code with one parity bit (the eighth) for error checking
and only 128 codes can be sent with 7 bits.

Modem Assembly and Checkout

Assembly of the modem presented few problems largely
because the instructions were more or less step by step,
unlike the instructions for the RS232 board. It is worth noting,
however, that the company tacks an extra charge on to any
repair if the components have been mounted "face down" so
that the values are not visible. This is the first time I have
seen this, but it does motivate good assembly practice.

The modem is attached to the interface by plugging the
projecting wire wrap pins on interface plug J2 into Jl on the
modem as shown in Figure 7. Care should be exercised as the

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pins are long, may not be properly aligned or straight and are
easily bent. Orientation of the heat sink on the interface is
important because it and transistor Q7 on the modem establish
the space between the two boards. I know from experience
that modem components, particularly the transformer and
crystal, will short out the RS232 board, producing expensive
odors. Byte-Back has recently included a case for the unit. I
wish I had one.

CIRCLE 4 ON READER SERVICE CARD

Figure 7. RS232 interface with piggyback modem.
(Note: Modular plug: Radio Shack 279-375.1

Connecting the modem to the telephone service may be a
problem although adequate instructions are given and the
newer units come with a modular plug. It is a good idea to
disconnect the modem from the telephone when not in use,
particularly in those parts of the country where electrical
storms are common. Since a telephone must be used for
dialing and answering, a duplex jack (Radio Shack # 279-357)
should be used, and the phone connected in parallel with the
modem.

It is not necessary to subscribe to a computer service to
check out the modem; all that is needed is a telephone
number. Of course, the service will evict anyone who cannot
produce a password at the proper time but most computer
services are patient and enough communication will take
place during the login attempt to verify proper terminal
function.

Since Byte-Back software is configured at the factory for
communication with CompuServe, I decided to visit them for
checkout. To get the local CompuServe number I called (800)
848-8990 and asked for a local number in my area. Since
Copuserve does not have a local number everywhere, I was
also prepared to use the University of Alabama at Huntsville
(UAH) bulletin board at (205) 895-6749 (ring once, call back
within 40 seconds). Many universities maintain such services.
So do many computer clubs. It should be understood, how-
ever, that these are amateur systems and they crash a lot, so
do not get discouraged.

With the modem plugged into the telephone line and a
valid telphone number the system is ready for checkout. This
is done by the following steps:

1) LOAD the modem software into the Sinclair.

2) Make sure that the computer is in the SLOW mode (the
software will not work on a ZX80 without a video upgrade).

3) RUN the program and answer the prompts by entering
"O" and "N" for originate and echo. In a few moments the
words "BYTEBACK INC. GLASS TTY" will appear on the
screen, indicating that the system is standing by waiting for
an answer tone from another modem,

4) Dial the host computer. When it answers, its modem will
generate an answer tone (2000Hz). This will be followed
immediately by the originate tone (1000Hz) from the Byte-
Back unit. If this occurs, the unit can be considered at least
partially functional.

September/October 1 983 ® SYNC

y dog barked. Then the host computer filled my
screen with garbage and hung up!

5) Do not hang up the phone at this time! Either wrap the
receiver in a towel, smother it in a pillow or, if it has a
modular handset, remove the handset plug from the telephone
base. This is important! Once when I was on line to Compu-
Serve, my dog barked, causing the host computer to fill my
screen with garbage and hang up.

h) After the two modems exchange tones, the host will
immediately start sending a message that will appear on the
screen. If the message is in clear English text, the system
works, and communications have been established! Go out
and celebrate. If assorted jumbled characters, try PEEKing
the mode instruction to make sure that the configuration
matches that required by the host.

What Will It Do?

The Byte-Back modem system as delivered will convert the
Sinclair ZX80/81 into what is popularly known as a "dumb
terminal." Also it furnishes the capability to connect that
terminal to a host computer via the telephone. As with most
"dumb terminals" the user can dial up a properly equipped
remote computer, command it to execute programs local to
it, and receive the results on the TV attached to the Sinclair.

With the software supplied, the only way to retain the
output is to halt the terminal program, reenter Basic and
COPY the screen to the printer (if one is available). If this is
done, however, the remote site may hang up the phone. Also

Figure 8 . Remote job execution.

Figure 8a. Fortran listing.

eeiee progrrm hero (input .output)

00130
00190
00200
00210
3F9.
00220
3

230 +
0024-0

t_(-|l_r- TC , Tt , U , l_r

IF (R . EQ .0.0) STOP

S= (R+B+C) y2.0

RDCL=S* (S-R) * (S-B) * (S-C)

IF (RDCL.LT.0.0! GOTO 2

RREfi-SSRT (RDCL)
PRIMT 101 (q s r odfo
GOTO 1 '

..^R^ii: 1 !^?!? nRE -

102 FORMAT (10H S IDES ' RRE,
F Ind' 1?M INUR| - ID TRIRNGLE)

RERDY .

157

Figure 8b. Sample run.
*> *» c. o

SIDES RRE 3.0000
.0000

RRER IS 7.64-4.4-E+00
? 5, 10, 15

SIDES RRE 5.0000

.0000

RRER 13 0.
7 5,5,5

SIDES RRE 5.0000
.0000

RRER TS 1.0S25E+01
*?
*? 0.0,0,0

6.0000

10.0000 15

5 . 0000

SRU

1.114- UNTS.

RUN COMPLETE,

■
14- Q

it is not possible to "download" or copy software from any
remote site, even another Sinclair. Having examined the
terminal software (available from Byte-Back) for $10 and
probably worth it, I have good news: the limitations mentioned
are not in the hardware. I should point out that the software
works well; it is just limited, but then so is the cost.

Since I have installed my modem, I have used it to com-
municate with several systems. I have been able to command
the execution of Fortran and Cobal jobs on the large main-
frame computer where I work. An example of this is shown in
Figure 8a; sample output is shown in Figure 8b. This program
was executed about 15 miles from my home, both the listing
and the output were COPYed on my Sinclair. Yes, I am
running Fortran jobs from a Sinclair computer.

On a more mundane level I have exchanged notes with
Apple, Atari, and other computer owners on the bulletin
board at the University and determined on CompuServe that
it was raining in Brazil. A complete listing of what is available
out there in "computerland" is beyond the scope of this
article, but one thing I have enjoyed is the encyclopedia
research service that several large systems offer. Just enter
the subject, and within a few seconds the complete encyclo-
pedia article appears on the screen!

After some experience, I feel that the larger systems are
easier to communicate with. The Sinclair is definitely limited
in some respects, and it helps to deal with a system that has
enough capability to adjust. Things like page size, interrupt
and abort codes often need to be negotiated, and most of the
major services can. For example. I have found it helpful to
direct the host to send upper case characters only. The Byte-
Back software can deal with any incoming ASCII code, but it
converts lower case into inverse video. This results in a
display that looks a bit like a ransom note, and it is hard to
read (Figure 9).

The modem software will LOAD in 2K. The price of the
Byte-Back kit is about $120. The TS1000 now costs less than
$70 (even as low as $50). So for less than $200 you can
command the resources of a computer that costs in excess of
$16 million! That ought to satisfy anyone's power hunger!

If I have inspired you to share my disease and get into data
communications with your Sinclair, give me a call on the
UAH bulletin board and leave me a message. I would like to
hear from you. *m

Figure 9. Authors ZX80 on line to CompuServe.
(Note: The telephone handset is unplugged.)

September/October 1983 « SYNC

107

3D Monster Maze and Mothership David Gmsjean

In 3D Monster Maze you are in a maze
running from T. (Tyrannosaurus) Rex.
The object is to get out alive!

The game begins with a circus barker
telling you the background of the maze.
He then gives you the choices of seeing
the instructions, quitting, or starting. The
computer takes less than 30 seconds to
set up the maze, and then the action
begins.

You are walking (or running) down a
corridor which has dark black walls, while
the corridors branching off your path
have grey walls. Messages at the bottom
of the screen give you reports such as
"He is hunting for you," "Rex has seen
you," and "RUN he is beside you." Each
step increases your score by 5 points.
When you reach the exit, you are awarded
200 points and put in a new maze. The

instructions do not tell you what the exit
looks like, but, when you see it, you know
that you have escaped.

The game is very easy to get used to,
but it is difficult to win consistently. The
controls are simple: the arrow keys are
used to indicate left, right, and forward
(up).

The program uses Basic and mostly

machine code (to produce and move the
pictures quickly). Although the pixels on
the TS1000 are rather coarse, the 3-D
simulation is marvelously effective. The
illusion of a corridor with extension is
created by converging lines, and Rex gets
larger as he gets closer. The simplicity
and speed of this program make it fun for
all ages.

David Grosjean, 50 Kings Rd.
07928.

Chatham, NJ

PERSONAL WEALTH
ACHIEVER

DO YOU KNOW THE WAYS TO BUILD VAST
WEALTH WITH A MINIMUM OF TIME AND
EFFORT - AND OFTEN LITTLE CAPITAL?

MOST PEOPLE THINK THEY ARE TOO BUSY
MAKING MONEY TO EFFECTIVELY MANAGE
IT, THEY MISTAKENLY BELIEVE THE
PROCESS OF WEALTH ACCUMULATION IS
COMPLICATED, MYSTERIOUS, AND TIME
CONSUMING. AS A RESULT THEIR NET
WORTH IS ONLY A FRACTION OF WHAT
IT COULD BE, AND THEIR FINANCES
ARE IN A STATE OF CONFUSION.

PERSONAL WEALTH ACHIEVER IS A 16K.
MENU DRIVEN PROGRAM THAT WILL HELP
YOU INCREASE INCOME AND NET WORTH
WITH LITTLE TIME, EFFORT, OR RISK.
THIS INTER-REACTIVE PROGRAM HELPS
YOU, STEP BY STEP, TO GET FINANCES
UNDER CONTROL AND TO EXPAND YOUR
EARNINGS CAPABILITY. PROVEN WEALTH
ACCUMULATORS, WITH GRAPHIC DISPLAYS,
WILL HELP YOU TO GAIN FINANCIAL
INDEPENDENCE. THIS PROGRAM COULD

IS PR
BE WORTH A FORTUNE TO YOU

cS?s

is looo isoo

£?*£

0&£

tclelek

15 Central Wav
Suite 169
Kirkland. WA 98033

108

5VNEBGIC5
UNLimiTED

PRESENTS USER-FRIENDLY HOME UTILITY
PROGRAMS FOR YOUR ZX81 TS1000

NUTRIFILE I & II I16K E4K)

Develop your own recipe file and access recipe by name,
meal or type of dish Ad|ust ingredients for different
number of servings Develop menu plans and grocery
lists

NUTRIFILE I I16KI Handles 30 recipies $12.50

NUTRIFILE II I64KI Handles 120 Recipies and
contains additional nutritional data for menu planning

114 00

HEALTHFILE I16K/64KI

Maintain family health records Keep track of family birth
data, heights, weights immunization, illnesses and other
health data File space for doctors and hospitals Also
basic First Aid and Poison Control data Program allows
user-friendly expansion to 64K S10.50

CALENOARFILE (16K/64K)

Establish your own databank of appointments, remin-
ders important dates and recurring events Access data
by month, date, subiect or keywords Program allows
user-friendly expansion to 64K S12 50

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ORDER H1001 $29.95

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Does digging through the manual j
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September/October 1983 ® SYNC

Software Profile

Name: 3D Monster Maze

Type: Arcade game

System: 8K ROM; 16K RAM

Format: Cassette

Summary: Remarkably effective 3D

simulation with a fun game. Rex is

after you i

Price: $14.95 plus $2 s&h per order.

Manufacturer:
Melbourne House Software
Dept. CS, 347 Reedwood Dr.
Nashville, TN 37217

Mothership is a space combat game
with a 3-D simulation. The top half of the
screen shows the stars of outer space in a
stationary background while the bottom
half shows a trench (somewhat like the
one in Star Wars when the Death Star is
destroyed). You are in your fighter flying
down this trench. Your controls (left,
right, up, down, and fire) are easy to get
used to. The illusion of depth comes from
the use of converging lines to show the
trench, and the illusion of flight from the
constantly changing display.

5L_|nt=

Software Profile
Name: Mothership
Type: Arcade Game
System: 8K ROM; 16K RAM
Format: Cassette

Summary: A challenging game and
excellent use of graphics make this a
superb game and a lot of fun.
Price: $16.95.
Manufacturer:

Softsync, Inc.

14 E. 34th St.

New York, NY 10016

At first you are fighting drones which
emanate from the huge mothership seen
cruising back and forth across the top of
your screen. They fly towards you while
shooting, or they simply fly at you on
suicide missions. The drones are worth
from 100 to 500 points depending on
where you are in the corridor. The higher
up in the corridor you are, the more the
drones are worth, and the faster every-
thing moves. After shooting ten drones
without losing one of your ships, the drone
attack stops, and the mothership begins
shooting at you. You must hit it three
times before it is destroyed. You are
awarded from 1000 to 5000 points de-
pending on where you are in the corridor.

There are three levels of difficulty. In
the first, the drones do not shoot at you.
In the second, the drones do shoot at
you. The third level is just like the second
except that it is much more difficult. You
do not crash if you hit the sides of the
corridor in the first two levels, but you do
in the third. Up to two people can play
individually.

This game is simple, yet it can get very
difficult. The speed, smoothness, and
excellent use of graphics make this a

superb game and a lot of fun.

It is not surprising then that Mothership
is one of the five award winning programs
in the Timex Sinclair category at this
year's Consumer Electronics Showcase
and that it is the only U.S. software pack-
age bought by Sinclair for British distri-
bution. Three other Softsync entries are
also among the five award winners:
Mazogs (reviewed in SYNC 2:6), Quest
for the Holy Grail, and TS Destroyer.

■4# ITf|£f H HMO !#-■/

3-Dimensional Graphics?

When you steer your Starlite
fighter down the Zarway space
corridor you won't believe your
eyes because the graphics are
so good and the game so fast.
S16.95

%^T 1

MOTHERSHIP 16K

For Your Timex/Sinclair T00Q

You can find MOTHERSHIP and all of SOFTSYNC S
wide variety of programs for the TS1000/ZX8I at your
local retail store or write us for a free catalog and
program listing. Prices range from SI4.95 to S19.95.

Please rush me I MOTHERSHIP program I enclose SI6.95
♦ Si 50 shipping and handling (N.Y residents add
sales tax)
U Please send me a free catalog 5 program listing.

NAME

ADDRESS

C(TY_

SOFTSYNC. INC.. 14 East 34th St New York, NY 10016
1212)685-2080

CIRCLE 61 ON READER SERVICE CARD

September/October 1983 ° SYNC

109

Brick BuSter Paul Thomson

"Brick Buster" is a game in which the
player earns points by knocking out as
many of the bricks in the playing area as
possible. On-screen scoring and a high
score memory are provided for competi-
tive playing. The active part of the game
is written in machine code for fast action.
The rest of the game is in Basic for ease
of programming.

Using the machine code loader pro-
gram in Figure 1 (or your own program, if
you prefer), enter the machine code from

Figure 1. Machine code loader.

1 REM 1234.5573901234.567890123
456 7890 123 45 £■"'39012345673 90 123 45
6739012345678901234.5673901234.567
890123456739012345578901234.56789
012 "456 7890 1234567390 12345673901
234567390123*5673901234567390123
45678901234567890123456739012345
6789012345673901234.5673901234.567
390123456739012 34567390
10 LET L=16514

LET L» = "4.082"

SCROLL

40 PRINT LS,
50 INPUT St
IF fl$= 5

70 PRINT fit

rHEN STOP

30 IF fl* = '

THEN GOTO 30
90 POKE L,16*C0DE RJ+CODE fl»(2

-476

100

-E"T L=L + J

110 LET fl*=fl*(3 TO )

120 LET 8=4.

130 LET R=CODE L$ (B) +1

140 IF n>*3 THEN GOTO 20O

150 LET L$=L$i TO B-1)+CHR$ fl

160 FOR F=B-1 TO 2

170 LET L$=LJ+"0"

130 NEXT F

190 GOTO 30

200 LET B=B-i

210 GOTO 130

the second column in Figure 2 into the
first REM statement. Check the address
on the screen after each entry to make
sure that it corresponds to Figure 2. After
the machine code is entered, be very
careful not to alter the REM statement in
any way. Save it now in case of a crash
later.

Paul Thomson. 361 W. Windsor. Lombard. IL
60148.

4082

111016

LD DE , 1 6 1

40B5

010516

LD BC, 1605

40B8

START:

LD A.B

408"?

FE02

CP 02

408B

2007

JR NZ.MISS

408D

3E04

LD A, 04

4<">8F

32AC40

LD (BINST), A

4092

1803

JR LWALL

4094

FE1B

MISS:

CP 18

409b

RET Z

4097

LWALL:

LD A,C

409B

FE02

CP 02

409A

2007

JR NZ.RWALL

409C

3E0C

LD A, OC

409E

32AD40

LD (CINST), A

4nCl

1 H09

JR BINST

40A3

FE1F

FtWALL:

CP IF

40A5

2005

JR NZ, BINST

40A7

3E0D

LD A,OD

40A9

32AD40

LD (CINST), A

40 AC

BINST:

DEC B

40 AD

CINST:

DEC C

40AE

CD5541

CALL ADDR

4061

LD A, (HL)

40B2

FEOB

CP 08

40B4

2016

JR NZ.SUBS

40B6

CD6A4 1

CALL SCORE

40B9

3AAC40

LD A, (BINST)

40BC

FE05

CP 05

40BE

2007

JR NZ. BOUNCE

40C0

3E04

LD A, 04

40C2

32AC40

LD (BINST), A

40C5

1805

JR SUBS

40C7

3E05

BOUNCE:

LD A, 05

40C9

32AC40

LD (BINST), A

40CC

3680

SUBS:

LD (HL),BO

40CE

CDE040

CALL PADDLE

40D1

CD8241

CALL DELAY

40D4

CDE040

CALL PADDLE

40D7

CDB241

CALL DELAY

40DA

3600

LD (HL),00

40DC

1BAA

JR START

40DE

NOP

40DF

NOP

4OE0

PADDLE:

PUSH HL

40E1

PUSH BC

40E2

LD B.D

40E3

LD C,E

40E4

DB04

IN A. 04

40E6

FE3B

CP 3B

40E8

2008

JR NZ.MVLF

40EA

LD A,C

40EB

FE1D

CP ID

40ED

280D

JR Z.PRPADL

40EF

INC C

4OF0

1 BOA

JR PRPADL

40F2

FE2F

MVLF

CP 2F

40F4

2006

JR NZ, PRPADL

4 OF 6

LD A.C

Figure 2. Machine code listing.

110

Initialize paddle position.
Initialize ball position.
Has ball hit back wall*?

No. Go check tor a miss.

Yes. Change vertical direction.

Go check left wall.

Did ball get past paddle?
; Yes. Return to Basic.
; No. Has ball reached left wall?

No. Go check right wal 1 .

Yes. Change horizontal direction.

Go change ball direction.
Has ball reached right wall?

Yes. Change horizontal direction.

No. Change position o-f ball.
(B: vertical ; Ci hori zontal ) .
; Find new address of ball.

Is there a brick in new ball position 7

No. Go move bal 1 .
Yes. Go increment score.
Make ball bounce off brick in
opposi te vertical di recti on.

Print ball in new posi ti on.

Move paddl e.

Delay.

Move paddle.

Del ay.

Print blank in old ball position.

Go back to start.

Save bal 1 position.
Get paddle posi t i on .

Find what key i s pressed .

Move right?
; No. Go check for move lef t .
; Yes. Is paddle at right end?

Yes. Go print paddle.

No. Move paddl e posi tion to right .

Go print new paddle.

Move left?

No. Go print paddle.

Yes. Is paddle at left end?

September/October 1983 « SYNC

40F7

FE01

CP Ol ;

40F9

2801

JR Z.PRPADL ;

4C.IFB

DEC C ;

40FC

CD5541

PRPADL

: CALL ADDR |

40FF

3600

LD (HL),00 |

4101

INC HL I

4102

3603

LD (HL),03 )

4104

INC HL (

4105

3603

LD <HL),03 ;

4107

INC HL ;

4108

3600

LD (HL).OO I

410A

DEC B ;

41 OB

CD554 1

CALL ADDR 1

410E

3AAD40

LD A, (CINST) !

411 1

FEOC

CP OC i

4113

200F

JR NZ.MIDPAD i

4115

LD A, (HL) i

4116

FE80

CP BO i

41 IB

200A

JR NZ,MIDPAD S

411A

3E0D

LD A,OD ;

411C

32AD40

LD (CINST), A ;

411F

3E05

LD A, 05 !

4121

32AC40

LD (BINST),A i

4124

0602

MIDPAD

LD B,02 i

4126

TWICE

INC HL i

4127

LD A, (HL) »

4128

FEBO

CP 80 ;

412A

200C

JR NZ,CQNT !

412C

3E05

LD A, 05 i

412E

32AC40

LD (BINST),A !

4131

EXX ;

4132

pop BC ;

4133

06 1 4

LD B, 14 i

4135

PUSH BC ;

4136

exx ;

4137

NOP ;

4138

10EC

CDNT:

DJNZ TWICE ;

413A

INC HL i

413B

3AAD40

LD A, (CINST) ;

413E

FEOD

CP OD ;

4140

200F

JR NZ, ENDPAD ;

4142

LD A, (HL) ;

4143

FE80

CP 80 ;

4145

200A

JR NZ, ENDPAD ;

4147

3E0C

LD A,OC ;

4 14Q

32AD40

I n irikCTi /\ •

414C

3E05

LD A, 05 ;

414E

32AC40

LD (BINST).A

4151

ENDPAD:

LD E,C i

4152

POP BC ;

4153

POP HL i

4154

RET ;

4155

ADDR:

PUSH DE ;

4156

PUSH BC ;

4157

2AOC40

LD HL.D-FILE ;

415A

PUSH BC ;

415B

0600

LD B,00 ;

415D

ADD HL.BC ;

415E

POP BC i

415F

112100

LD DE.0021 i

4162

1003

TEST:

DJNZ AGAIN ;

4164

POP BC ;

4165

POP DE ;

4166

RET ;

4167

AGAIN:

ADD HL.DE I

4168

1BFB

JR TEST !

416A

SCORE:

PUSH HL ;

416B

2A0C40

LD HL.D-FILE ;

416E

JNC HL ;

416F

Inc HL ;

4170

INC HL i

4171

INC HL ;

4172

CHECK:

LD A, (HL) ;

4173

INC A :

4174

FE26

CP 26 J

4176

2803

JR Z, CARRY i

4178

LD (HL),A i

4179

1 BOS

JR ENDSCR i

417B

361C

CARRY:

LD (HL),1C ;

417D

DEC HL ;

417E

18F2

JR CHECK :

4180

ENDSCR:

POP HL ;

4181

RET ;

4182

DELAY:

PUSH BC i

4183

010002

LD 8C.0200 ;

4186

CNTDWN:

DEC BC !

4187

LD A,B i

4188

OR C ;

4189

20FB

JR NZ, CNTDWN :

418B

POP BC :

418C

RET ;

Yes. Go print new paddle.

No. Move paddle position to le-ft.
; Find paddle address.
; Print paddle.

Check if ball hit paddlf

Check left end o-f paddli

Check center sections o-f paddle
for hit.

If ball hits center of paddle,
project ball one extra posi t i on
vertically to make sure all bricks
can be hit.

Check right end of paddle.

Get bal 1 position.

Save paddle position.
Save bal 1 posi tion.
Get display address.

Fi nd hor i zontal posi t i on .

Get ball posi t i on .
Get paddle posi t i on.

Find vertical position.

Save bal 1 address.

Get display address.

Fi nd tens posi t i on in score.

Add 10 to score.

Get ball address.

Save ball posi t ion .
Load delay.

Cont i nue with delay.
Get ball position.

ScreenMate

ScreenMate's Llghtpen and InterFace for the Atari*
Joystick adds versatility to your ZX81 or TS1000

• Play Action Games

• Direct Interaction with
the TV Screen.

■ Features a "Piggy-back
Add On Feedthrough

• Draw and Doodle

• Ideal for Educational
Programs

• Independent of
Keyboard

$39.95 includes

• Lighipen wiih Joystick Interface

• User Guide • 90 Day Limited Warranty

• All Postage and Handling

^T* ScreenMate Program Cassette

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Interface Innovations

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AND SAVE $$$

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September/October 1983 « SYNC

SAVINGS * SAVINGS

We are offer ing quality prograns for

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sold fron Canada and sold at Canadian

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For the Canadian purchaser, there is

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Dealer Inquiries Weconel

SOPHIA SYSTEMS

15122 Pheasant Drive
Surrey, B.C. Canada, V3R 4X6

111

Next, enter the Basic part of the game.
Enter the lines in Figure 3 over the first
program. Be sure to leave the REM state-
ment alone. Make sure you enter the
Basic just as in Figure 3. The line notes
will help.

After the Basic part of the game is
entered, you are all set to play. Again to
be safe, SAVE the whole program now
by typing RUN 500. When you LOAD the
program to play again, it will start running
by itself. After it is LOADed, the com-
puter will ask you to enter the speed of
play. Five or greater is suggested for the
beginner. After you enter the speed, the
playing field is drawn. You have 5 balls
per game. You serve the ball by pressing
S. The paddle is controlled by the 5 and 8
keys. Each brick is worth 10 points. At
the end of the game, if you have the
highest score so far. you get to enter your
name which will stay in memory until
your score is beaten or the program is
stopped.

Line notes:
70:3, zero (4), 6 (26), 4.
90:8,5.

120: A (32).

190: Space (32).

280: In inverse: PRESS "P" TO PLAY
AGAIN. 5

is 39a E
press f ro I

LET DI5P=PEEK ( 16395) +PEEK

(16397) tS56

LET BE5T=0

CLS

PRINT "ENTER SPEED 1 TO 9

(1=FA3TEST) "

PRINT AT 3,6; " <=S. . . .3=>

S*SERUE"

INPUT I

IF I<1 OR I>9 THEN GOTO 30

POKE 16773,1

CLS

FOR F=l TO 20

PRINT AT F,0,"1",TAB 31, 1

100

NEXT F

110

FOR F=l TO 7

120

Figure 3. The Basic program. .

•BEST SCORE

130 NEXT F
14.0 FOR F=5 TO
150 POKE 16556
160 POKE 16513
170 IF INKEY*<

25 STEP 5

5
F

THEN GOTO 1~

i.30 RAND USR 16514

190 PRINT AT 21,0; "

200 NEXT F

£10 PRINT AT 0,11; "GOME OUER '

220 LET SCORE =0

230 FOR R=l TO 4

240 LET SCORE =SCGRE+ (PEEK (DISP
+R+1) -28) *10** (4-R)

250 NEXT R

260 IF SCORE >BEST THEN GOSUB 40

270 PRINT AT 10 . 1 ,
S ",BEST; " BY "; Z$

230 PRINT AT 12,4;

HBHH39".at 12.4,
" to play again"
290 if inkey*="p" then goto 15

300 GOTO 230

400 CLS

410 LET BEST=SCORE

420 PRINT AT 2,2;"Y0U NOU HAUE
THE BEST SCORE"

430 PRINT AT 4,1; "ENTER YOUR NA
ME (1-9 LETTERS.) "

440 INPUT Z*

450 RETURN

500 SAUE "BRICKBUSTES

510 RUN

Reader

Service No. Advertiser

A ■+■ As^nriRtp*;

A. + Associates

—

A. + Associates

—

AB Engineering

Aardvark

—

Abbey Tape Duplicators

Abersoft

—

Advanced Energy Systems

Aerco

—

Air Capital Software

—

Artisan Electronics

Atto Software

Audiovision

George Bezushko

Bi-Pak

Brainchild Computer Works

—

Frank A Burr

Busyness Magazine

Byte Back

Bytesize Products

Cinagro Software

—

Circle Chess

Comprocsys

—

Compuball

Compusoft Publishing

—

Compusport

—

Computech

Computer Add-ons

Computer Assistance

Computer Continuum

The Computer Trader

Computer-Wear Software

Cottage Technology

—

Creitech

—

Curry Computing

—

Day Design

Data Assette

Data Con

Discount Software

Down East Computers

Downsway California

—

D-Ram Products

E-Z Key

E Arthur Brown & Company

—

E- Arthur Brown & Company

Eagle Sales

Earthscenes

—

Nissim Elmaleh

Page

Index to Advertisers
Reader
Service No. Advertiser

hlesixty

—

Bob Fingerle

—

The Fourth Design

—

Friendly Computer

21
94

G Russell Electronics

Ganhart/Earthings

—

The Golden Stair

—

P Hargrave

Heath Computer Services

—

Horizon Simulations

106
45

Hunter

Hurricane Electronics

Independence Research

—

Indiana Software Group

Intercomputer

101

—

Interface Innovations

—

JGS

—

JST Enterprises

Jameco

K2 Electronics

9fi

—

Katt's Computer

—

Kinetronics Corp

—

Lambs Software

Leading Edge

—

Lyon Ware

Melbourne House Software

—

Memotech Corp

—

Memotech Corp

Microsystems Specialists

—

Mopsy

Mule Electronics

C-?

P.C.E

Peak

Peoples Computer Supply

Pleasantrees

108

Quicksilva

R.I.ST

RAM Products

Ramex International

Reston Publishing

Robotec

—

Rom-Pak

Page

53
76

97
93

81
62
89
97
47
98
56
69

62
98

111

111
93
33

40
63
95

C-4

23
1
30-31
71
63
45

81
74
75
48

C-3

46
79
38

Reader

Service No. Advertiser

— Savage Software

— Semper

— Semper
M Sieder
Simplex Software
Sinclair Place
Sinclair Place
Sinclair Place
Sinclair Supply Shack
Singh Computer Supplies
Sinware
Siriusware
Softsync. Inc
Solutions
Sophia Systems
Speedware
Spyder Electronics
Strategem Cybernetics
Suntronics
Syber Inc.
Sybex

Sync Master
Synergies Unlimited

57
41
58
59

61
62

63
64
65
66
67
68
69

70 Tapemasters

— Teletek

— 3G Company

71 Timeworks

— Toco Technology

— Troiano Software Co.

72 21st Century

73 2-Bit

74 Ultimate Blackwood

75 Upstate Labs

76 User Friendly Research

— User Friendly Software

— WT Associates

77 Wayne Green Books

78 York- 10 Computerware

— Z-Tron international

— ZX Data

79 Zebra Systems Inc

80 Zebra Systems Inc

— Euaene Zweio

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i!S HERE

^sreToi^

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Awesome software which

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maximum.

Enjoyed by millions in

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ritain's leading
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BUY A BANANA. SAVE A BUNCH.

Meet the Banana;* 1 the very
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Gorilla. 1 "

At $249.95 retail it's an ideal
and inexpensive companion for
personal computers like Apple !
(or Apple "look alikes'such as
Franklin® or Albert®), Tl.
Commodore," TRS-80," Kaypro,"
Timexr Osborne," etc.

After that, it's merely com-
parable to other printers that can
cost up to three times as much:
10" carriages (to handle standard
9V2" paper), 80 columns, graphics
capability, 10 characters per inch
(expandable to 5 cpi) draft-quality
print (for perfectly acceptable
form letters, data processing,

business reports, etc.) tractor
feed (for precise alignment and
quick loading), parallel or serial
interface (take your pick), self-
inking ribbon cassette (for long
life and easy installation), 10
portable pounds in weight, and
compatibility with so many of the
most popular personal computers
on the market.

Plus its printhead features a
unique single-hammer design that
eliminates a lot of moving parts, to
eliminate a lot of annoying repairs.

That's the Banana: silly name,
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